NFC smart card and working method of NFC smart card

Abstract

The present invention provides an NFC smart card and a working method of the NFC smart card. The NFC smart card includes a card body, a contactless chip and an NFC antenna; the contactless chip and the NFC antenna are arranged inside the card body; the NFC antenna includes a first coupling antenna, a second coupling antenna and a receiving antenna, the first coupling antenna is electrically connected to the receiving antenna, the second coupling antenna is connected to the contactless chip, the first coupling antenna is coupled to the second coupling antenna, and the first coupling antenna is coupled to the receiving antenna; in the thickness direction of the card body, the first coupling antenna is not in contact with the second coupling antenna, the first coupling antenna is not completely overlapped with the second coupling antenna, and the energy received by the second coupling antenna is less than the energy received by the receiving antenna; the sum of the area of ​​the receiving antenna and the area of ​​the first coupling antenna is greater than the area of ​​the second coupling antenna. Under the condition of ensuring that the NFC smart card receives external signals normally, the internal chip of the NFC smart card is prevented from being burned.

Description

Technical Field

[0001] The present invention relates to the field of wireless near field communication, and in particular to an NFC smart card and a working method of the NFC smart card. Background Art

[0002] NFC smart cards can obtain electromagnetic wave signals from card readers, and obtain energy through electromagnetic wave signals to achieve communication between NFC smart cards and card readers. The coil obtains electromagnetic field signals from the electromagnetic field, thereby generating current and voltage. When the current flows through the chip inside the NFC card, it supplies energy to the chip to work. The magnitude of the current depends on the strength of the electric field.

[0003] Existing wireless charging devices can charge mobile phones wirelessly, and their power can reach 100W. However, when an NFC card is close to a wireless charging device, the NFC card can generate high voltage, and the chip cannot withstand the excessively high voltage, causing the chip to burn out.

[0004] Chinese patent CN201383160Y discloses a smart card, which includes a smart card chip, a first antenna that communicates with a card reader contactlessly, and a second antenna that communicates contactlessly with the first antenna and is connected to the antenna contacts of the smart chip. The first antenna includes a second coil and a third coil, and the second antenna includes the first coil. In order to ensure the best communication effect and the minimum energy transmission loss, the smart card makes the first coil and the third coil have the same size, overlap in space and have the minimum spacing. However, since the second coil is connected to the third coil, the third coil can completely transfer the energy obtained by the second coil to the first coil, so that the smart card chip completely receives the energy transmitted by the first coil, which may burn the smart card chip.

[0005] The NFC signal range-extending antenna includes a primary coil and a secondary coil, which are formed by winding a winding wire, the primary coil is coupled with the antenna of the NFC reader, and the secondary antenna is coupled with the antenna of the NFC carrier. The primary coil is coupled with the secondary coil, so that the electromagnetic wave signal of the communication between the antenna of the NFC reader and the antenna of the NFC carrier can be relayed, and the induction distance between the antenna of the NFC reader and the antenna of the NFC carrier can be increased. However, the Zengcheng antenna is used to enhance the induction distance between the antenna of the NFC reader and the antenna of the NFC carrier, and cannot weaken the electromagnetic wave signal. When used on an NFC card, the NFC card is still easily burned. Summary of the invention

[0006] A first object of the present invention is to provide an NFC smart card which reduces the energy transmitted by the antenna.

[0007] A second object of the present invention is to provide a working method of an NFC smart card using the above NFC smart card.

[0008] To achieve the first objective of the present invention, the present invention provides an NFC smart card, comprising a card body, a contactless chip and an NFC antenna; the contactless chip and the NFC antenna are arranged inside the card body; the NFC antenna comprises a first coupling antenna, a second coupling antenna and a receiving antenna, the first coupling antenna is electrically connected to the receiving antenna, the second coupling antenna is connected to the contactless chip, the first coupling antenna is coupled to the second coupling antenna, and the first coupling antenna is coupled to the receiving antenna; in the thickness direction of the card body, the first coupling antenna and the second coupling antenna at least partially overlap, and the first coupling antenna and the second coupling antenna do not contact; in the thickness direction of the card body, the first coupling antenna and the second coupling antenna do not completely overlap, and the energy received by the second coupling antenna is less than the energy received by the receiving antenna; the sum of the area of ​​the receiving antenna and the area of ​​the second coupling antenna is greater than the area of ​​the second coupling antenna.

[0009] It can be seen from the above scheme that the antenna formed by the first coupling antenna and the receiving antenna receives external energy. Since the receiving antenna is laid around the card body, the intensity of the NFC smart card induction is not affected when the NFC smart card is in use. The strength of the received signal is proportional to the size of the antenna area, and the sum of the areas of the first coupling antenna and the receiving antenna is greater than the area of ​​the second coupling antenna. Therefore, when the receiving antenna receives an external signal, its high energy can only be added to the receiving antenna. Since the area of ​​the second coupling antenna connected to the chip is small, the second coupling antenna does not contact the first coupling antenna, so the energy received by the second coupling antenna is less than the energy received by the receiving antenna, thereby ensuring that the chip will not burn while receiving the signal. Since the first coupling antenna and the second coupling antenna do not completely overlap, while ensuring that the second coupling antenna can receive the energy of the first coupling antenna, the energy received by the receiving antenna generates a large amount of energy loss when it is transmitted to the second coupling antenna, and the second coupling antenna cannot receive all the energy of the receiving antenna, so that the energy received by the second coupling antenna is less than the energy received by the receiving antenna. While receiving the energy, the chip will not be burned due to excessive energy received by the second coupling antenna.

[0010] In a further solution, in the thickness direction of the card body, each coil of the first coupling antenna and each coil of the second coupling antenna are arranged in a staggered manner.

[0011] It can be seen that the first coupling antenna and the second coupling antenna are not completely overlapped by staggered arrangement of the coils of the first coupling antenna and the coils of the second coupling antenna.

[0012] In a further solution, in the thickness direction of the card body, the first coupling antenna is arranged axially symmetrically along the axis of the contactless chip, and the second coupling antenna is arranged axially symmetrically along the axis of the contactless chip.

[0013] It can be seen that the second coupling antenna is arranged axially symmetrically along the axis of the contactless chip so that the second coupling antenna can better transmit current to the contactless chip, and the first coupling antenna is arranged axially symmetrically along the axis of the contactless chip so that the first coupling antenna can smoothly transmit signals to the second coupling antenna.

[0014] In a further solution, the second coupling antenna and the contactless chip form a closed loop, and the first coupling antenna and the receiving antenna form a non-closed loop.

[0015] It can be seen that the first coupling antenna and the receiving antenna form a non-closed loop, ensuring that the receiving antenna does not generate heat, thereby ensuring that the NFC smart card does not heat up due to excessive energy received by the receiving antenna and thus burn out.

[0016] In a further solution, the first coupling antenna and the receiving antenna are arranged on a conductive wire, and the first coupling antenna and the receiving antenna are formed by winding the conductive wire.

[0017] It can be seen that the energy of the receiving antenna can be transmitted to the first coupling antenna.

[0018] In a further embodiment, the receiving antenna includes a first coil and a second coil, the first end of the first coil is connected to the first end of the first coupling antenna, and the second end of the first coil is connected to the first end of the wire; the first end of the second coil is connected to the second end of the first coupling antenna, and the second end of the second coil is connected to the second end of the wire.

[0019] It can be seen that the receiving antenna receives the electromagnetic field signal through the first end and the second end.

[0020] In a further solution, the area of ​​the receiving antenna is larger than the area of ​​the second coupling antenna.

[0021] It can be seen that, by making the area of ​​the second coupling antenna smaller than the area of ​​the receiving antenna, it is ensured that the energy received by the second coupling antenna is smaller than the energy received by the receiving antenna.

[0022] To achieve the second purpose of the present invention, the working method of the NFC smart card provided by the present invention applies the above-mentioned NFC smart card; the receiving antenna receives a first electromagnetic wave signal of an external device, and transmits the first electromagnetic wave signal to a first coupling antenna; the second coupling antenna receives a second electromagnetic wave signal formed by the first coupling antenna, and the second coupling antenna converts the second electromagnetic wave signal into an induced current, and transmits the induced current to a contactless chip.

[0023] In a further solution, the energy of the second electromagnetic wave signal is less than the energy of the first electromagnetic wave signal.

[0024] It can be seen from the above solution that since the sum of the area of ​​the receiving antenna and the area of ​​the first coupling antenna is larger than the area of ​​the second coupling antenna, the energy of the second electromagnetic wave signal is smaller than the energy of the first electromagnetic wave signal, ensuring that the chip is not burned. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an NFC smart card embodiment of the present invention.

[0026] Figure 2 It is a structural exploded view of an NFC smart card embodiment of the present invention.

[0027] Figure 3 is a cross-sectional view of an embodiment of an NFC smart card of the present invention.

[0028] Figure 4 is a circuit diagram of an embodiment of an NFC smart card of the present invention.

[0029] Figure 5 It is a flow chart of an embodiment of a working method of an NFC smart card of the present invention.

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0031] In the present invention, the NFC smart card is provided with a first coupling antenna, a second coupling antenna and a receiving antenna, and the area of ​​the second coupling antenna is smaller than the sum of the area of ​​the first coupling antenna and the area of ​​the receiving antenna, and the second coupling antenna is not in contact with the first coupling antenna, so that the energy received by the second coupling antenna is smaller than the energy received by the receiving antenna.

[0032] NFC smart card example:

[0033] See also Figure 1 The NFC smart card includes a card body 1, an NFC antenna and a contactless chip 12 are arranged inside the card body 1. Figure 2 The NFC antenna includes a first coupling antenna 13, a second coupling antenna 11 and a receiving antenna 14. The first coupling antenna 13 is electrically connected to the receiving antenna 14. The second coupling antenna 11 is connected to the contactless chip 12, and the second coupling antenna 11 and the contactless chip 12 form a closed loop. The first coupling antenna 13 is coupled to the second coupling antenna 11, and the first coupling antenna 13 is coupled to the receiving antenna 14.

[0034] See also Figure 2 and Figure 4, and the first coupling antenna 13 and the receiving antenna 14 are arranged on a wire, and the first coupling antenna 13 and the receiving antenna 14 are formed by winding the wire. The receiving antenna 14 includes a first coil 141 and a second coil 142, the first end of the first coil 141 is connected to the first end of the first coupling antenna 13, and the second end of the first coil 141 is connected to the first end of the wire; the first end of the second coil 142 is connected to the second end of the first coupling antenna 13, and the second end of the second coil 142 is connected to the second end of the wire. Since the first end of the wire is not connected to the second end, the first coupling antenna 13 and the receiving antenna 14 form a non-closed loop. Due to the mutual inductance of the receiving antenna 14 and the first coupling antenna, the electromagnetic field signal is received by the first coil and the second coil, so as to realize the transfer of the electromagnetic field signal to the second coupling antenna 11. Since the first coupling antenna 13 and the receiving antenna 14 form a non-closed loop, when the receiving antenna 14 receives high energy, the receiving antenna does not generate heat because a closed loop is not formed, thereby protecting the card body 1 from heating and affecting the chip operation.

[0035] See also Figure 3 In the thickness direction of the card body, the first coupling antenna 13 and the second coupling antenna 11 at least partially overlap, and the first coupling antenna 13 and the second coupling antenna 11 do not contact each other. The first coupling antenna 13 and the second coupling antenna 11 partially overlap, so that the signal of the first coupling antenna 13 can be transmitted to the second coupling antenna 11. Further, in the thickness direction of the card body, the first coupling antenna 13 and the second coupling antenna 11 do not completely overlap. Further, in the thickness direction of the card body 1, each coil of the first coupling antenna 13 and each coil of the second coupling antenna 11 are arranged in a staggered manner. In the thickness direction of the card body, the first coupling antenna 13 is arranged axially symmetrically along the axis of the contactless chip 12, and the second coupling antenna 11 is arranged axially symmetrically along the axis of the contactless chip 12. The incomplete overlap between the first coupling antenna 13 and the second coupling antenna 11 makes it impossible for the energy of the first coupling antenna 13 to be completely transmitted to the second coupling antenna 11, that is, at least a part of the first coupling antenna 13 does not overlap with the second coupling antenna 11. In this way, the energy received by the second coupling antenna 11 is less than the energy received by the receiving antenna 14, thereby reducing the energy received by the contactless chip 12 connected to the second coupling antenna 11, but ensuring that the second coupling antenna 11 can receive the signal of the first coupling antenna 13, so that the chip is not burned.

[0036] The sum of the area of ​​the receiving antenna 14 and the area of ​​the first coupling antenna 13 is greater than the area of ​​the second coupling antenna 11, and further, the area of ​​the second coupling antenna 11 is smaller than the area of ​​the receiving antenna 14. Since the second coupling antenna 11 is not in contact with the first coupling antenna 13, and further, the second coupling antenna 11 is not in contact with the wire wound to form the first coupling antenna 13 and the receiving antenna 14, and the area of ​​the second coupling antenna 11 connected to the contactless chip 12 is small, when the second coupling antenna 11 receives the signal of the first coupling antenna 13, the energy received by the second coupling antenna 11 is less than the energy received by the receiving antenna 14, thereby ensuring that the contactless chip 12 will not be burned. Since the second coupling antenna 11 and the contactless chip 12 form a closed loop, when the second coupling antenna 11 receives the signal from the first coupling antenna 13, an induced current can be formed, and the contactless chip 12 can establish communication with the outside.

[0037] Furthermore, the receiving antenna 14 is arranged around the card body 1 to ensure that the receiving antenna 14 can sensitively receive signals from external devices without affecting the induction strength of the NFC smart card.

[0038] Working method embodiment of NFC smart card:

[0039] See also Figure 5 The working method of the NFC smart card applies the above NFC smart card embodiment, firstly executing step S11, the receiving antenna 14 receives the first electromagnetic wave signal of the external device, and transmits the first electromagnetic wave signal to the first coupling antenna 13. Since the area of ​​the receiving antenna 14 does not change, the receiving antenna 14 can sensitively receive the signal of the external device.

[0040] After receiving the first electromagnetic wave signal, the first coupling antenna 13 transmits the first electromagnetic wave signal to the second coupling antenna 11. Since the electromagnetic wave signal received by the second coupling antenna 11 is the weakened first electromagnetic wave signal, the weakened first electromagnetic wave signal is set as the second electromagnetic wave signal. The second coupling antenna 11 performs step S12, where the second coupling antenna 11 receives the second electromagnetic wave signal sent by the first coupling antenna 11, and the second coupling antenna 11 converts the second electromagnetic wave signal into an induced current.

[0041] Since the second coupling antenna 11 and the contactless chip 12 form a closed loop, step S13 is executed, and the second coupling antenna 11 outputs the induced current to the contactless chip 12, so that the contactless chip 12 starts working. Among them, since the sum of the area of ​​the receiving antenna 14 and the area of ​​the first coupling antenna 13 is larger than the area of ​​the second coupling antenna 11, the energy of the second electromagnetic wave signal is smaller than the energy of the first electromagnetic wave signal, ensuring that the contactless chip 12 is not burned.

[0042] The above are only preferred embodiments of the present invention, but the design concept of the invention is not limited thereto. Without departing from the concept of the present invention, more other equivalent embodiments may be included. It is obvious to those skilled in the art that various changes, readjustments and substitutions can be made without departing from the protection scope of the present invention.

Claims

1. An NFC smart card, comprising a card body, a contactless chip and an NFC antenna; the contactless chip and the NFC antenna are arranged inside the card body; Features: The NFC antenna includes a first coupling antenna, a second coupling antenna and a receiving antenna, the first coupling antenna is electrically connected to the receiving antenna, the second coupling antenna is connected to the contactless chip, the first coupling antenna is coupled to the second coupling antenna, and the first coupling antenna is coupled to the receiving antenna; In the thickness direction of the card body, the first coupling antenna and the second coupling antenna at least partially overlap, and the first coupling antenna and the second coupling antenna do not contact; In the thickness direction of the card body, the first coupling antenna and the second coupling antenna do not completely overlap; The energy received by the second coupling antenna is less than the energy received by the receiving antenna; The sum of the area of ​​the receiving antenna and the area of ​​the first coupling antenna is greater than the area of ​​the second coupling antenna; In the thickness direction of the card body, each coil of the first coupling antenna and each coil of the second coupling antenna are arranged in a staggered manner; In the thickness direction of the card body, the first coupling antenna is arranged axially symmetrically along the axis of the contactless chip, the first coupling antenna smoothly transmits the signal to the second coupling antenna, and the second coupling antenna is arranged axially symmetrically along the axis of the contactless chip; The second coupling antenna and the contactless chip form a closed loop, and the first coupling antenna and the receiving antenna form a non-closed loop.

2. The NFC smart card according to claim 1, characterized in that: The first coupling antenna and the receiving antenna are arranged on a conductive wire, and the first coupling antenna and the receiving antenna are formed by winding the conductive wire.

3. The NFC smart card according to claim 2, characterized in that: The receiving antenna comprises a first coil and a second coil, the first end of the first coil is connected to the first end of the first coupling antenna, and the second end of the first coil is connected to the first end of the wire; The first end of the second coil is connected to the second end of the first coupling antenna, and the second end of the second coil is connected to the second end of the wire.

4. The NFC smart card according to any one of claims 1 to 3, characterized in that: The area of ​​the receiving antenna is larger than the area of ​​the second coupling antenna.

5. The working method of the NFC smart card is characterized in that: An NFC smart card as claimed in any one of claims 1 to 4; The receiving antenna receives a first electromagnetic wave signal from an external device, and transmits the first electromagnetic wave signal to a first coupling antenna; The second coupling antenna receives the second electromagnetic wave signal formed by the first coupling antenna, and the second coupling antenna converts the second electromagnetic wave signal into an induced current, and transmits the induced current to the contactless chip.

6. The working method of the NFC smart card according to claim 5, characterized in that: The energy of the second electromagnetic wave signal is less than the energy of the first electromagnetic wave signal.

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