Radio frequency identification (RFID) ring with coil antenna

Abstract

The present invention refers to a Radio Frequency Identification (RFID) ring having a main body and comprising an electronic module with a RFID chip, and an RFID antenna electrically connected to the RFID chip, wherein the RFID chip is configured to communicate with an external reader and to perform a predefined operation, such as a payment operation, and the RFID antenna is configured to provide energy to the RFID chip. In the RFID ring according to the present invention, the RFID antenna is a coil antenna comprising more than one winding and the windings form the main body of the RFID ring.

Description

[0001] RADIO FREQUENCY IDENTIFICATION (RFID) RING WITH COIL ANTENNA

[0002] TECHNICAL FIELD

[0003] The present invention refers to the field of Radio Frequency Identification (RFID) devices. In particular, the present invention refers to the field of RFID rings.

[0004] STATE OF THE ART

[0005] RFID rings are commonly employed for different everyday applications, for instance, to unlock a RFID enabled mobile device or another object, such as a vehicle or a door, to authorize payments or transactions, to share data with other devices, and to start predefined applications with custom settings.

[0006] An example of a RFID ring is disclosed in document US 5,832,296, which is directed to a self- contained, finger-wearable interface device that communicates with electronic devices. This device comprises several sensing mechanisms, such as pressure and force sensors, and electronic controllers and transmitters, it resembles a ring and is adapted to be worn on a user’s finger.

[0007] Another example of a RFID ring is disclosed in document EP 3 490 400, which refers to a near field communication (NFC) ring that can be read by nearby NFC-enabled devices. The NFC ring comprises an annular shell and a NFC transponder mounted on the annular shell, wherein the NFC transponder has a coil antenna that has a plurality of turns extending around the entire circumference of the annular shell. The NFC transponder, including the coil antenna, may be sealed from the surrounding environment by an annular cover.

[0008] Document EP 3 490 400 has the disadvantage that the material used for forming the annular shell encircling the coil antenna must be a non-metal material and must not block or interfere with the electro-magnetic field generated by the external reader, in order to allow communication between the antenna and the reader. The material forming the annular shell can be for instance a ceramic material, which is however fragile and does not provide an optimal support for the antenna.

[0009] RFID rings should comply with different technical and aesthetic standards. For example, they should ensure a wide range of directions for communication with external readers in the field of radio-frequencies and, at the same time, their appearance should be appealing, since they should be worn by a user and hence should be visible from other people.

[0010] On the contrary, most RFID rings known at the state of the art are not considered aesthetically appealing and are not appreciated in the luxury market. Moreover, there is a constant need to develop alternative configurations for the antennas of the RFID rings that can operate in the area of nearfield communication with electromagnetic coupling.

[0011] It is therefore an object of the present invention to provide an RFID ring which solves one or more of the problems outlined above.

[0012] SUMMARY

[0013] According to a first aspect of the present invention, a Radio Frequency Identification (RFID) ring is provided, the RFID ring having a main body and comprising:

[0014] An electronic module, comprising an RFID chip configured to communicate with an external reader and to perform a predefined operation, such as a payment operation;

[0015] An RFID antenna electrically connected to the RFID chip and configured to provide energy to the RFID chip;

[0016] Wherein the RFID antenna is a metal coil antenna comprising more than one winding, and the windings form the main body of an RFID ring.

[0017] This configuration is advantageous because the RFID ring ensures an optimal operation in inductive coupling applications, while providing an appealing aesthetic appearance to the RFID ring, because the resulting main body of the RFID ring obtained from the metal coil antenna appears to be entirely metal-based. Moreover, since the metal coil forms the main body of the RFID ring, it is directly exposed to external electro-magnetic fields generated by external readers, hence it has a better communication performance.

[0018] The RFID ring according to the present invention is simple and efficient in transmitting electronic signals by means of inductive coupling.

[0019] In the present disclosure, it is to be understood that the coil antenna forming the main body of the RFID ring may be described as a helix having a central axis, wherein each helix turn forms one of the windings of the coil antenna. Accordingly, the statement that the coil antenna comprises “more than one winding” should be interpreted as indicating that the coil antenna may comprise an integer or a half-integer number of windings, wherein this number is higher than one, for instance the coil antenna may comprise one and a half windings, two windings, two and a half windings, three windings, or more. Moreover, in the present disclosure, it is to be understood that the main body of the RFID ring is entirely and exclusively formed by the windings of the coil antenna. Accordingly, the RFID ring is not covered by nor embedded in any additional annular shell.

[0020] The metal coil antenna may be made of any metal material, such as nickel, copper, gold, silver, or the like, that ensure conduction of electric signals.

[0021] Preferably, the RFID ring is a passive device which receives a powering signal from the external reader. Preferably, the RFID ring requires no battery for communicating with the external reader.

[0022] According to an embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID antenna is partially or entirely made of a noble metal material, for instance gold, silver or platinum, or an alloy comprising at least a noble metal.

[0023] The advantage of this configuration is that noble metals ensure an optimal transmission of electric signals, while having a precious aesthetic appearance. Therefore, the RFID ring can be designed as a piece of jewelry.

[0024] Gold is typically used in jewelry making because it can be molded to form any shape. Preferably, gold is alloyed with other metals to improve its strength and malleability.

[0025] The use of platinum and of alloys comprising same to form the rings is advantageous in view of its hypoallergenic properties, and because it is corrosion and wear-resistant, ductile, malleable and dense.

[0026] Silver is typically used to make jewelry because it is malleable, ductile and harder than gold. Silver is advantageously alloyed with copper to make sterling silver

[0027] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein each winding is separated from a successive winding, along a direction parallel to the axis of the coil antenna, by a separating portion.

[0028] The advantage of this configuration is that shortcuts between successive windings of the coil antenna are avoided.

[0029] Preferably, the windings may be equally spaced from one another across the width of the RFID ring so as to confer a regular, symmetric and appealing appearance to the RFID ring.

[0030] Preferably, the spacing between the windings can be selected to assist in tuning the resonance frequency of the coil antenna. According to a preferred embodiment of the present invention, an RFID ring is provided, wherein the separating portion is filled with an insulating material, for instance plastic, resin, ceramics, and / or air.

[0031] The advantage of this configuration is that shortcuts between successive windings of the coil antenna are avoided.

[0032] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the electronic module is placed on the inside of the main body, so as to not be visible from the outside, and the RFID chip is placed in a recess formed in the electronic module.

[0033] The advantage of this configuration is that the other electronic components, such as the RFID chip or any capacitors, are hidden inside the main body of the RFID ring and are not visible to the user. The appearance of the RFID ring is hence that of a piece of jewelry, while the RFID ring is able to perform predefined operations by means of the RFID chip.

[0034] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID antenna is visible from the outside of the RFID ring.

[0035] This configuration is advantageous because the RFID antenna may be made of a precious metal material and it may be visible from the outside, to the user.

[0036] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID antenna has a first resonance frequency and the electronic module further comprises one or more capacitors for fine tuning the first resonance frequency.

[0037] This configuration is advantageous because it is possible to fine tune the resonance frequency of the antenna, depending to the predefined application, by using one or more capacitors integrated into the electronic module, without affecting the design of the windings of the coil antenna. In this way, the number of windings, their diameter, and the spacing between the windings may be designed based on aesthetic reasons, such as the dimensions of the finger or the wrist of the user, or the desired aesthetic appearance.

[0038] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID ring is shaped as a finger ring and the windings are configured to house a finger of a user.

[0039] This configuration is advantageous because a finger ring is commonly worn by users for aesthetic reasons. At the same time, by approaching the finger ring to an external reader, it is possible to performed predefined operations that require Radio Frequency communication, such as transactions operations.

[0040] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID ring comprises a number of windings comprised between four and ten, for instance small-sized rings may have a number of windings between six and ten, and largesized rings may have a number of windings between four and eight.

[0041] In the present disclosure, it is to be understood that the terms “small-size ring” and “large-size ring” refer to the ring sizes defined in ISO 8653:2016 standards: accordingly, a “small-size ring” refers to a ring having an ISO size between 49 and 60, corresponding to an inner diameter of the ring between 15.6 mm and 19.1 mm, and a “large-size ring” refers to a ring having an ISO size between 61 and 72, corresponding to an inner diameter of the ring between 19.4 mm and 22.9 mm

[0042] This solution is advantageous because the number of windings can be adapted to obtain a predefined resonance frequency for the antenna, but, at the same time, it can be designed to obtain a predefined thickness of the finger ring, depending on aesthetics considerations.

[0043] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID ring is shaped as a bracelet and the windings are configured to house a wrist of a user.

[0044] This configuration is advantageous because a bracelet is commonly worn by users for aesthetic reasons. At the same time, by approaching the bracelet to an external reader, it is possible to performed predefined operations that require Radio Frequency communication, such as transactions operations.

[0045] According to another embodiment of the first aspect of the present invention, an RFID ring is provided, wherein the RFID ring comprises a number of windings comprised between two and four, preferably three.

[0046] This solution is advantageous because the number of windings can be adapted to obtain a predefined resonance frequency for the antenna, but, at the same time, it can be designed to obtain a predefined thickness of the bracelet, depending on aesthetics considerations.

[0047] According to another aspect of the present invention, a method for operating a RFID ring is provided, the method comprising the following steps: Exposing the RFID ring to an alternating electro-magnetic field generated by an external reader, thereby generating an induced current within a coil antenna;

[0048] Powering up the RFID chip by means of the induced current;

[0049] Performing a predefined operation by means of the RFID chip.

[0050] This method is advantageous because it enables carrying out predefined operations requiring radio frequency communication, such as transactions, by simply wearing the ring or the bracelet and directing it towards an external reader, such as a NFC reader. The user may decide to wear the RFID finger ring or bracelet also for aesthetic reasons.

[0051] Preferably, communication between the RFID ring and the external electromagnetic reader is carried out at a resonance frequency of 13.56 MHz. Preferably, the communication protocols may be ISO / IEC14443, ISO / IEC 15693 and / or Qi as interface standard for wireless power transfer using inductive charging.

[0052] FIGURES

[0053] Fig. 1 schematically illustrates a three-dimensional view of a RFID ring according to an embodiment of the present invention.

[0054] Fig. 2 schematically illustrates a front view of a RFID ring according to another embodiment of the present invention.

[0055] Fig. 3 schematically illustrates a three-dimensional view of a RFID ring according to another embodiment of the present invention

[0056] DETAILED DESCRIPTION

[0057] In the following, the present invention is described with reference to particular embodiments, as is illustrated in the enclosed figures. However, the present invention is not limited to the particular embodiments described in the following detailed description and shown in figures. Instead, the described embodiments simply exemplify the different features of the present invention, the scope of which is defined in the claims. Further modifications and variations of the present invention will be clear to the skilled person.

[0058] In the following detailed description, the terms “right”, “left”, “top”, “bottom”, and variations thereon are employed with reference to the orientation shown in the figures. Fig. 1 schematically illustrates a three-dimensional view of a RFID ring according to an embodiment of the present invention.

[0059] The RFID ring 100 of Fig. 1 is shaped as a finger ring and is configured to be worn on a finger of a user. Preferably, the RFID ring 100 is a piece of jewelry.

[0060] The RFID ring 100 of Fig. 1 comprises a main body, which is entirely and exclusively formed by the windings 111 , 112, 113, 114, 115, and 116 of the coil antenna 110.

[0061] The coil antenna 110 forming the main body of the RFID ring 100 may be described as a helix having an axis A1 . Each helix turn forms one of the windings 111 -116 of the coil antenna 110.

[0062] Even if Figs. 1 and 2 show that the coil antenna 110 comprises six windings, it is to be understood that the coil antenna 110 may comprise any number of windings higher than one, for instance two, three, four, five, seven, or more. Moreover, even if this is not shown in Figs. 1 and 2, it is to be understood that the coil antenna 110 may even comprise any number of half windings, such as one and a half windings, two and a half windings, three and a half windings, or more.

[0063] The number of windings may be designed based on technical reasons, for instance for obtaining a predefined resonance frequency of the coil antenna, but also on aesthetic reasons, for instance for obtaining a predefined thickness of the ring. Preferably, small-sized rings may have more windings, e.g. between six and ten windings, compared to large rings, e.g. between four and eight.

[0064] The RFID ring 100 further comprises an electronic module 120 including an RFID chip 122, which is powered up by the coil antenna 110. The RFID chip 122 enables carrying out predefined operations, such as payment operations.

[0065] As can be seen in Fig. 1 , the electronic module 120 is placed on the inner side of the main body, so that it is not visible from the outside of the RFID ring 100 and does not affect its aesthetic appearance. The electronic module 120 is preferably accommodated in a recess milled in one of the antenna loops, and it is preferably mounted thereon by means of direct pressed die technology. The RFID chip 122 is mounted on the electronic module 120 by means of chip wire technology and glob topping. Opposite ends of the coil antenna 110 are electrically connected to the chip 120. In particular, the first winding 111 and the last winding 116 of the coil antenna 110 are directly connected to the RFID chip 122 to enable electrical communication. For instance, the first and last windings 111 and 116 are directly connected to the two pins of the chip 122A and 122B known as ANT 1 and ANT2. Preferably, gold wire bonding, ribbon soldering, TAB (tape) bonding, or other similar methods, may be used to connect the RFID chip 122 to the windings of the coil antenna 110, and / or the RFID chip 122 to the electronic module 120.

[0066] Preferably, the RFID chip 122 may comprise a capacitor and / or a resistor that can be used to fine-tune the resonance frequency of the coil antenna 110 when connected to the RFID chip 122. Preferably, a small circuit with sensors and / or a battery (not shown in Fig. 1 ) may be also mounted on the electronic module 120 and connected to the RFID chip 122.

[0067] The communication between the electronic module 120, which may comprise the RFID chip 122, the sensors, and / or the battery, and the external environment is enabled by the coil antenna 110 by means of electromagnetic coupling. Preferably, communication between the electronic module 120 and the external electromagnetic reader is carried out at a resonance frequency of 13.56 MHz. Preferably, the communication protocols may be ISO / IEC14443, ISO / IEC 15693 and / or Qi as interface standard for wireless power transfer using inductive charging.

[0068] According to a preferred embodiment, the windings 111-116 of the coil antenna 110 may be advantageously made of a noble metal, such as gold, silver or platinum, or an alloy comprising at least a noble metal. In fact, noble metals ensure optimal transmission of electrical signals, while having a pleasant aesthetic appearance. Preferably, the windings 111-116 of the coil antenna 110 are polished to make the RFID ring 100 suitable for the luxury market.

[0069] According to another preferred embodiment, the windings 111-116 of the coil antenna 110 may comprise a metal core coated by a layer of a noble metal, such as gold, silver or platinum, by means of electroplating. The metal core may be made for instance of copper, nickel, or the same noble metal used for the coating.

[0070] According to another preferred embodiment, the windings 111 -116 of the coil antenna 110 may comprise a copper core on which a layer of photoresist is applied.

[0071] Fig. 2 schematically illustrates a front view of the RFID ring 100 of Fig.1.

[0072] In Fig. 2 it is possible to see the windings 111 , 112, 113, 114, 115, and 116 forming the coil antenna 110.

[0073] The windings 111 , 112, 113, 114, 115, and 116 are separated from each other by a separating portion 130. The separating portion 130 can be selected to assist in tuning the coil antenna 110.

[0074] The separating portion 130 may be filled with an insulating material, for instance plastics, like polyester, polyimide films or fiberglass, resins, ceramics, like enamel or varnish, and / or air. In this way, the windings 111 , 112, 113, 114, 115, and 116 are isolated from each other and the electrical signals can be efficiently transmitted by the coil antenna 110, without any shortcuts. Preferably, the insulating material of the separating portion 130 is nearly invisible, in order to not affect the aesthetic appearance of the RFID ring 100.

[0075] In Fig. 2, the windings 111-116 are all equally spaced from one another.

[0076] According to alternative configurations (not shown), the spacing between the windings 111-116 may not be constant across the coil antenna 110 and each separating portion 130 between two successive windings may be different from another separating portion 130.

[0077] According to an alternative embodiment, the windings 111 , 112, 113, 114, 115, and 116 may be in contact with each other, but each winding may be made of a conductive material coated with an insulated material, such as a plastic, resin, or ceramic material.

[0078] Fig. 3 schematically illustrates a three-dimensional view of a RFID ring according to another embodiment of the present invention.

[0079] The RFID ring 100’ of Fig. 3 is similar to the RFID ring 100 of Figs. 1 and 2, but it differs from them in the dimensions. In fact, the RFID ring 100’ is shaped as a bracelet and is configured to be worn on a wrist of a user. Preferably, the RFID ring 100’ is a piece of jewelry.

[0080] Since the RFID ring 100’ shaped as a bracelet has a larger diameter with respect to the RFID ring 100 shaped as a finger-ring, the number of windings of the coil antenna 110 is reduced. Preferably, the number of windings is between two and four.

[0081] With reference to the illustrative embodiment of Fig. 3, the coil antenna 110 comprises four windings 11 T, 112’, 113’ and 114’.

[0082] The coil antenna 110 forming the main body of the RFID ring 100’ may be described as a helix having an axis A2. Each helix turn forms one of the windings 111 ’, 112’, 113’, 114’ of the coil antenna 110.

[0083] As can be seen in Fig. 3, the electronic module 120 is placed on the inner side of the main body, so that it is not visible from the outside of the RFID ring 100’ and does not affect its aesthetic appearance. The RFID chip 122 is accommodated in a recess milled in the electronic module 120, and it is preferably mounted thereon by means of direct pressed die technology. Opposite ends of the coil antenna 110 are connected to the chip 120. In particular, the first winding 111 ’ and the last winding 114’ of the coil antenna 110’ are directly connected to the RFID chip 122 to enable electrical communication. For instance, the first and last windings 111 ’ and 114’ are directly connected to the two pins of the chip 122A and 122B known as ANT 1 and ANT2.

[0084] During operation of the RFID ring 100 or 100’, the user wears the finger ring 100 or the bracelet 100’ and exposes it to an alternating electro-magnetic field generated by an external Near Field Communication (NFC) reader, for instance a reader for authorizing payment operations. In this way, an induced magnetic field parallel to the axis A1 or A2 and an induced current are generated within the coil antenna 110 of the RFID ring 100 or 100’. The induced current powers up the RFID chip 120, which enables performing a predefined operation with the NFC reader, such as a payment operation.

[0085] By using a coil antenna 100 wound around the finger or the wrist of the user, the corresponding RFID ring 100 or 100’ can be optimally coupled to the NFC-reader when the axis A1 or A2 of the RFID ring 100 or 100’ is perpendicular to the surface of the reader. This orientation is best achieved when the user wearing the RFID ring 100 or 100’ uses a knocking-type action.

[0086] Even if the present invention has been described with reference to the embodiments described above, it is clear to the skilled person that it is possible to apply different modifications, variations and improvements of the present invention in light of the teachings described above and the field, and within the scope of the enclosed claims, without departing from the scope and purpose of the present invention.

[0087] Finally, those fields considered known to the skilled person have not been described to avoid covering in a useless way the described invention.

[0088] REFERENCE NUMBERS

[0089] 100, 100’: RFID ring

[0090] 110: coil antenna

[0091] 111 , 112, 113, 114, 115, 116: windings of the ring

[0092] 111 ’, 112’, 113’, 114’: windings of the bracelet

[0093] 120: electronic module

[0094] 122: RFID chip

[0095] 122A, 122B: pins of the chip

[0096] 130: separating portion 140: capacitor

Claims

CLAIMS1. A Radio Frequency Identification (RFID) ring (100, 100’) having a main body and comprising:An electronic module (120), comprising an RFID chip (122) configured to communicate with an external reader and to perform a predefined operation, such as a payment operation;An RFID antenna (110) electrically connected to said RFID chip (122) and configured to provide energy to said RFID chip (122);Wherein said RFID antenna (110) is a metal coil antenna comprising more than one winding (111 , 112, 113), and said windings (111 , 112, 113) form said main body of said RFID ring (100).

2. The RFID ring (100, 100’) of claim 1 , wherein said RFID antenna (110) is partially or entirely made of a noble metal material, for instance gold, silver or platinum, or an alloy comprising at least a noble metal.

3. The RFID ring (100, 100’) of claim 1 or 2, wherein each winding (111 , 112, 113) is separated from a successive winding (111 , 112, 113), along a direction parallel to the axis of said coil antenna, by a separating portion (130).

4. The RFID ring (100, 100’) of claim 3, wherein said separating portion (130) is filled with an insulating material, for instance plastic, resin, ceramics, and / or air.

5. The RFID ring (100, 100’) of any of previous claims, wherein said electronic module (120) is placed in a recess formed in said main body, so as to not be visible from the outside, and said RFID chip (122) is placed on said electronic module (120).

6. The RFID ring (100, 100’) of any of previous claims, wherein said RFID antenna (110) is visible from the outside of said RFID ring.

7. The RFID ring (100, 100’) of any of previous claims, wherein said RFID antenna (110) has a first resonance frequency and said electronic module (120) further comprises one or more capacitors (140) for fine tuning said first resonance frequency.

8. The RFID ring (100, 100’) of any of previous claims, wherein said RFID ring (100) is shaped as a finger ring and said windings (111 , 112, 113) are configured to house a finger of a user.

9. The RFID ring (100, 100’) of claim 8, wherein said RFID ring (100) comprises a number of windings (111 , 112, 113) comprised between four and ten, for instance small-sized rings having an ISO size between 49 and 60 as defined in ISO 8653:2016 standards may have a number of windings between six and ten, and large-sized rings having an ISO size between 61 and 72 as defined in ISO 8653:2016 standards may have a number of windings between four and eight.

10. The RFID ring (100, 100’) of any of previous claims, wherein said RFID ring (100’) is shaped as a bracelet and said windings (11 T, 112’, 113’, 114’) are configured to house a wrist of a user.11 . The RFID ring (100, 100’) of claim 10, wherein said RFID ring (100’) comprises a number of windings (11 T, 112’, 113’, 114’) comprised between two and four, preferably three.

12. A method for operating a RFID ring (100, 100’) according to any one of claims 1 to 11 , said method comprising the following steps:Exposing said RFID ring (100, 100’) to an alternating electro-magnetic field generated by an external reader, thereby generating an induced current within said coil antenna (110);Powering up said RFID chip (122) by means of said induced current;Performing a predefined operation by means of said RFID chip (122).

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