Transponder with spiral antenna

Abstract

To provide a transponder provided with a spiral antenna that has a large maximum communication distance.SOLUTION: The present invention relates to a transponder (1, 10) including an electronic system (3) for managing the sending and receiving of data and a spiral antenna (2). The spiral antenna (2) includes a wound strip material forming a plurality of coils (11). The electronic system (3) is connected to the spiral antenna (2) by two connection points (6, 7) located on the wound strip material. The coils (11) included between the two connection points (6, 7) form a first set of coils (4, 14), and the spiral antenna (2) includes a second set of coils (5, 15) extending outside the connection points (6, 7). Also, the present invention relates to an electronic device, particularly a timepiece, including such a transponder (1).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of information transmission and communication, in particular to transponders equipped with a transmitting and / or receiving antenna. [Background technology]

[0002] A transponder is an electronic device that is configured to transmit and receive data. Passive RFID (Radio Frequency Identification) transponders exist, which are often intended to encode and record products.

[0003] Other passive transponders are, for example, terminals or bank cards for contactless payments etc. Such transponders are generally of the NFC (Near Field Communication) type and allow data transfer over short distances.

[0004] Communication is established between two terminals, each of which comprises an electronic system for managing and recording data and an antenna for transmitting and receiving data to the other terminal.

[0005] The antenna is important because it determines the operating distance of transmission / reception between these terminals, but the dimensions of the antenna must be very small to limit the size of the terminals. For this purpose, there are antennas that include a section in the form of a spiral, which allows to have a sufficient antenna length while occupying a minimum amount of space. The number of turns determines the inductance of the antenna. To ensure sufficient inductance and communication up to the maximum communication distance, there are connection points with the electronic system at both ends of the spiral section, i.e. at the outer and inner ends of the spiral section.

[0006] If this is not enough, the communication distance can be increased by placing a second antenna in parallel with the first antenna, which acts as a resonant circuit so that the nominal frequency of both sets of antennas remains unchanged with respect to the nominal frequency of the spiral section alone. Thanks to this second antenna, the communication distance can be increased.

[0007] However, the improvements are limited and not always sufficient for the desired applications. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to improve upon the above-mentioned problems and to provide a transponder comprising an electronic system for managing the transmission and reception of data and a spiral antenna, the spiral antenna comprising a wound strip forming a number of turns, the electronic system being connected to the spiral antenna by means of two connection points located on the wound strip. [Means for solving the problem]

[0009] This transponder is innovative in that the first set of turns includes the outer turns of the spiral antenna and the second set of turns includes the inner turns of the spiral antenna.

[0010] Thanks to the second set of turns extending outwards between the connection points of the electronic system, the communication range of the spiral antenna can be increased by 10-20%, thus allowing the transponder to meet certain operating standards while maintaining a small size.

[0011] Thanks to the invention, certain electronic devices, for example timepieces of the watch type (e.g. wristwatches, pocket watches) can be used for NFC type data transfer, in particular with a payment system that can be used as a bank payment card for short distances.

[0012] In one particular embodiment of the invention, the first set of turns comprises the outer turns of the spiral antenna and the second set of turns comprises the inner turns of the spiral antenna.

[0013] In one particular embodiment of the invention, the first set of turns and the second set of turns are linked such that the spiral antenna is contiguous.

[0014] In one particular embodiment of the invention, the first and second sets of turns are separated such that the spiral antenna is discontinuous, with a gap at the boundary between the first and second sets of turns.

[0015] In one particular embodiment of the invention, the first set of turns and the second set of turns extend in the same plane.

[0016] In one particular embodiment of the invention, the second set of turns is not connected.

[0017] In one particular embodiment of the invention, the transponder comprises a resonant circuit that includes the second set of turns.

[0018] In one particular embodiment of the invention, the resonant circuit comprises a capacitor connected to the second set of windings by two connection points, such that an inner third set of windings is located between the two connection points of the capacitor.

[0019] In one particular embodiment of the invention, the inner second set of turns includes an inner fourth set of turns that extends contiguously inwardly of the inner third set of turns.

[0020] In one particular embodiment of the invention, the inner fourth set of turns is not connected.

[0021] In one particular embodiment of the invention, the inner third set of turns and the inner fourth set of turns are connected such that the second set of turns is contiguous.

[0022] In one particular embodiment of the invention, said transponder is an NFC type transponder, in particular one that plays a role in payment methods.

[0023] The invention further relates to an electronic device comprising a transponder as described above.

[0024] In one particular embodiment of the invention, the electronic device is a timepiece, such as a watch.

[0025] In one particular embodiment of the invention, said spiral antenna forms the face of a timepiece.

[0026] The objects, advantages and features of the present invention will become more apparent upon reading the description of some embodiments thereof, given for illustrative purposes and not intended to limit the scope of the invention, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a top view of a first embodiment of a transponder according to the present invention; FIG. [Diagram 2] FIG. 4 is a schematic diagram of a top view of a second embodiment of a transponder according to the present invention. [Diagram 3] 1 is a schematic diagram of a top view of a watch equipped with a transponder according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In figures 1 and 2 two embodiments of a transponder 1, 10 are shown, which comprises an electronic system 3 for managing the transmission and reception of data and a spiral antenna 2, 12. The communication protocol is for example of the NFC (Near Field Communication) type. This technology is used in particular for payment methods, for example using payment cards which allow to pay remotely using so-called "contactless" terminals.

[0029] The spiral antenna 2, 12 comprises a wound strip of material forming a number of turns 11.

[0030] The electronic system is for example an integrated circuit including a chip arranged to manage NFC type communication. The electronic system 3 is connected to the spiral antenna 2 by means of two connection points 6, 7 on the wound strip. The turn 11 between the two connection points 6, 7 forms a first set of turns 4, 14.

[0031] According to the invention, the spiral antenna 2,12 includes a second set of turns 5,15 extending outwardly between the connection points 6,7.

[0032] The second set of turns 5, 15 includes adjacent turns closest to the center of the spiral antenna 2, 12 and having the smallest radius of curvature. In Fig. 1, the second set of turns 5, 15 includes all inner turns from the connection point closest to the center of the spiral antenna 2, 12. The second set of turns 5, 15 thus includes here at least 25 turns. The number of second sets of turns 5, 15 can naturally be less or more, for example about 10, 20, 30 or more.

[0033] Preferably, in these embodiments, the first set of turns 4,14 comprises the outer turns 11 of the spiral antenna 2 and the second set of turns 5,15 comprises the inner turns 11 of the spiral antenna 2,12.

[0034] The first set of turns 4, 14 and the second set of turns 5, 15 extend substantially in the same plane. Thus, the spiral antennas 2, 12 extend substantially in the same plane so as to minimize the thickness of the spiral antennas 2, 12. All turns 11 of the spiral antennas 2, 12 are wound in the same plane.

[0035] The first set of turns 4, 14 comprises several adjacent turns which are furthest from the centre of the spiral antenna 2, 12 and have the largest radius of curvature. In figures 1 and 2 the first set of turns 4, 14 comprises two turns. The first set of turns 4, 14 can of course comprise more turns, such as three, four, five or more, and can consist of one turn or less than one turn.

[0036] The two connection points 6, 7 are preferably located at the two ends of the outer first winding set 4, 14, i.e. the two connection points 6, 7 are located at the furthest and closest points to the center of the first winding set 4, 14, respectively.

[0037] A pair of wires 25 connect the two connection points 6, 7 to the electronic system 3. These wires 25 are for example soldered or glued to the connection points 6, 7 and to an integrated circuit.

[0038] In the first embodiment shown in Fig. 1, the first set of turns 4 and the second set of turns 5 are connected together in such a way that the spiral antenna 2 is continuous, thus resulting in a continuous spiral antenna 2 formed by the two sets of turns.

[0039] Also, the second set of windings 5 ​​is not connected, i.e. there is no connection between the second set of windings 5 ​​and the electronic system 3 or any of the other components.

[0040] The second set of windings 5 ​​makes it possible to improve the range of remote data transmission between this transponder 1 and other transponders or terminals. In fact, the second set of windings 5 ​​makes it possible to store more energy than is possible with only the first set of windings 4. Thus, thanks to this additional energy, the transmission distance can be increased.

[0041] The second embodiment in Figure 2 shows a spiral antenna 12 in which the first set of turns 14 and the second set of turns 15 are separated such that the spiral antenna 12 is discontinuous, i.e., the spiral antenna 12 has two separate portions, which are separated by a gap 8 at the boundary between the first set of turns 14 and the second set of turns 15. Thus, there is no direct connection between the two sets of turns 14, 15.

[0042] Following the inner side of the connection point 6, which is preferably the most central of the two connection points 6, 7, there is a gap 8. Thus, the two connection points 6, 7 are not connected to the second winding set 15.

[0043] In this embodiment, the transponder 10 comprises a resonant circuit 20. The resonant circuit 20 includes a second set of turns 15.

[0044] The resonant circuit 20 also comprises a capacitor 9 connected to the second set of windings 15. The capacitor 9 is connected to two connection points 18, 19. One connection point 18 is located at the end of the innermost turn 11 of the second set of windings 15. The other connection point 19 is located on an inner turn 11 closer to the center, such that some of the inner turns 11 are between the two connection points 18, 19 of the capacitor 9. The capacitor 9 is subsequently located inside the gap 8 between the first set of windings 14 and the second set of windings 15.

[0045] The inner third winding set 21 is therefore located between the two connection points 18 , 19 of the capacitor 9 .

[0046] Since the centrally-closest connection point 19 of the capacitor 9 is not located at the center of the spiral antenna 12, only some of the turns 11 of the second winding set 15 belong to the inner third winding set 21.

[0047] Thus, the second inner winding set 15 includes a fourth inner winding set 23 that extends inwardly of the third inner winding set 21. The fourth inner winding set 23 extends closer to the center than the connection point of the capacitor 8, and corresponds to the inner winding sets of the second inner winding set 15 excluding the third inner winding set 21.

[0048] The inner third winding set 21 and the inner fourth winding set 23 are connected such that the second winding set 15 is continuous.

[0049] The inner fourth winding set 23 is not connected, i.e. the fourth winding set 5 is not connected to the electronic system 3 or to any other component.

[0050] Thanks to this resonant circuit 20, this embodiment of the transponder allows for a data transfer range that is increased by 30-40%.

[0051] Such transponders can be used in electronic products, for example timepieces, which are arranged to carry out payments like bank cards. NFC type transponders allow for example payments over short distances, so-called "contactless".

[0052] In Fig. 3, a watch 30 is shown that includes a transponder according to the invention. The watch 30 has a case 31 that houses a timepiece movement, preferably an electronic movement, and a hand 32 that indicates the time. A transponder is also arranged in the case 31. In this embodiment, the spiral antenna 22 of the transponder is used as the face of the watch 30. The spiral antenna 22 is arranged under the crystal 33 of the watch 30. The hand 32 moves on the spiral antenna 22, which is visible through the crystal 33 by the user. In the case of the second embodiment, the electronic system 3, the contacts and the capacitor are arranged so as to be hidden under the spiral antenna 22.

[0053] If desired, a pattern may be formed on the top surface of the spiral antenna 22 for decorative purposes or to indicate time indexes or the like.

[0054] Naturally, the invention is not limited to the embodiments of the transponder and the electronic device described with reference to the drawings, and alternative forms are conceivable without departing from the scope of the invention. [Explanation of symbols]

[0055] 1, 10 Transponder 2, 12, 22 Spiral Antenna 3. Electronic Systems 4, 14 First set of turns 5, 15 Second set of turns 6, 7 Connection points 8 Gap 9. Capacitor 11 rolls 18, 19 Connection points 20 Resonant circuit 21 Third set of turns 23 Fourth Set of Rolls 25 Wire 30 Portable Watch 31 cases 32 needles 33 Windshield

Claims

1. A transponder (1, 10) comprising an electronic system (3) for managing the transmission and reception of data and a spiral antenna (2, 12, 22), The spiral antenna (2, 12, 22) comprises a wound strip forming a plurality of turns (11), the electronic system (3) is connected to the spiral antenna (2) by two connection points (6, 7) located on the wound strip, the turn (11) between said two connection points (6, 7) forms a first turn set (4, 14); the spiral antenna (2, 12, 22) includes a second set of turns (5, 15) extending from a connection point (6) among the connection points (6, 7) that is closest to a center of the spiral antenna (2, 12, 22) to an inside of the spiral antenna (2, 12, 22); the first set of turns (14) and the second set of turns (15) are separated such that the spiral antenna (2) is discontinuous; There is a gap (8) at the boundary between the first winding set (14) and the second winding set (15); The transponder (1, 10) further comprises a resonant circuit (20) including the second set of windings (15); The resonant circuit (20) comprises a capacitor (9) connected to the second set of windings (15) by two connection points (18, 19); An inner third winding set (21) is located between the two connection points (18, 19) of the capacitor (9). A transponder characterized by:

2. The first set of turns (4) comprises the outer turns (11) of the spiral antenna (2) and the second set of turns (5) comprises the inner turns (11) of the spiral antenna (2).

2. The transponder according to claim 1 .

3. The first winding set (14) and the second winding set (15) are arranged in the same plane.

3. The transponder according to claim 1 or 2.

4. The second winding set (5) is not connected to the electronic system (3).

3. The transponder according to claim 1 or 2.

5. The second winding set (15) includes an inner fourth winding set (23) that extends continuously to the inside of the inner third winding set (21).

2. The transponder according to claim 1 .

6. The inner fourth winding set (23) is not connected to the electronic system (3).

6. The transponder according to claim 5.

7. The inner third winding set (21) and the inner fourth winding set (23) are connected to form the continuous second winding set (15).

6. The transponder according to claim 5.

8. It is an NFC type transponder.

3. The transponder according to claim 1 or 2.

9. A device that plays a role in a payment method.

9. The transponder according to claim 8.

10. Equipped with a transponder (1, 10) according to claim 1 1. An electronic device comprising:

11. It is a timekeeping device like a portable watch.

11. The electronic device according to claim 10.

12. The spiral antenna (22) forms the face of the timepiece.

12. The electronic device according to claim 11.

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