CN215989208U

CN215989208U - Electronic devices and NFC systems

Info

Publication number: CN215989208U
Application number: CN202120375218.0U
Authority: CN
Inventors: 张功磊; 储嘉慧; 张琛; 王国龙; 常乐; 杨育展
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-02-18
Filing date: 2021-02-18
Publication date: 2022-03-08
Anticipated expiration: 2031-02-18

Abstract

The application provides an electronic device and an NFC system, and relates to the technical field of NFC. The electronic device includes an NFC antenna and a metal decorative piece, the metal decorative piece is connected with the NFC antenna, and the metal decorative piece radiates an electromagnetic field outward when an electrical signal is conducted. Generally speaking, these metal decorative parts are relatively large in size. By connecting with the NFC antenna, the return path of the NFC antenna is increased, thereby increasing the sensing area of the NFC antenna.

Description

Electronic device and NFC system

Technical Field

The present invention relates to the field of NFC technologies, and in particular, to an electronic device and an NFC system.

Background

Near Field Communication (NFC) is a short-range, high-frequency radio technology that transfers data and information by way of electromagnetic inductive coupling in the radio frequency portion of the operating spectrum. The NFC antenna can thus be equivalent to a transformer or impedance transformer.

Because NFC has characteristics such as low cost, convenient easy-to-use and richer intuition, all have the NFC function in most terminal equipment now. In the terminal device, the NFC antenna is provided in a single-ended common NFC antenna and a double-ended NFC antenna. The single-ended common NFC antenna is composed of a Flexible Printed Circuit (FPC), or a metal frame of a terminal device, or the FPC and the metal frame; the double-end NFC antenna is composed of an FPC, ferrite and gum.

In the single-ended common NFC antenna scheme shown in fig. 1, the FPC and the metal frame are connected by traces on a Printed Circuit Board (PCB). With the arrival of the 5G era, the frequency bands of the antennas on the terminal equipment become more and the frequency becomes higher, so that the slots of the frame structural member are more than those of the 4G era, the length of the branches of the metal frame is shortened, the length of the usable frame branches of the single-end common NFC antenna is shorter and shorter, the single-end common NFC antenna is more and more unfavorable for the NFC antenna, and the length of the antennas cannot meet the performance requirement.

In the two-terminal NFC antenna scheme as shown in fig. 2, the FPC and the ferrite are arranged inside the terminal device by means of a back adhesive. With the function of the terminal device increasing, the components stacked inside are more compact, and the index requirements of various functions are higher and higher, for example, the area of the heat sink required by thermal design is increased, the area of the double-end NFC antenna is further extruded, and the performance is affected.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problem, embodiments of the present application provide an electronic device and an NFC system.

In a first aspect, the present application provides an electronic device comprising: NFC antenna, metal decoration, with NFC antenna connection for outwards radiate the electromagnetic field when switching on the signal of telecommunication.

In this embodiment, the metal decoration (metal decoration) may be a metal part between the camera lens and the device housing on the smart device, a metal directional keypad of the "up/down/left/right" button on the remote controller, a metal ring on the sound box, a metal sound outlet protection ring on the sound box, and so on. Generally, the sizes of the metal decorating parts are large, the metal decorating parts can be connected with a chip through an FPC (flexible printed circuit) or a coil, a return flow path of the NFC antenna is increased, and therefore the induction area of the NFC antenna is increased.

In one embodiment, the metal decoration is one or more of a metal frame of a camera, a metal directional keyboard of a remote controller, a metal ring on a sound box, and a metal sound outlet protection ring on the sound box.

In one embodiment, the method further comprises: further comprising: and the flexible circuit board FPC is connected with the metal decorating part and is used for providing the electric signal and/or the outward radiation electromagnetic field for the metal decorating part.

In one embodiment, the NFC antenna comprises an FPC connected to the metallic decoration for providing the electrical signal and/or radiating an electromagnetic field outwards to the metallic decoration.

In one embodiment, the method further comprises: the metal decorating part is connected with the FPC through the wiring of the PCB.

In a second aspect, an embodiment of the present application provides an NFC system, including: an NFC chip, a matching circuit and an electronic device as each possible implementation of the first aspect.

Drawings

The drawings that accompany the detailed description can be briefly described as follows.

Fig. 1 is a circuit diagram of a single-ended NFC antenna design in the prior art;

fig. 2 is a circuit diagram of a dual-ended NFC antenna design in the prior art;

fig. 3 is a schematic diagram of an NFC system architecture according to an embodiment of the present application;

fig. 4 is a circuit diagram of an NFC system of a two-terminal NFC antenna;

fig. 5 is a circuit diagram of an NFC system with a single-ended NFC antenna;

FIG. 6 is a schematic view of a metal decoration on a mobile phone;

fig. 7 is a circuit diagram of a single-ended NFC antenna according to an embodiment of the present application;

fig. 8(a) is a schematic diagram of an NFC antenna including an FPC and a metal bezel provided in an embodiment of the present application when passive impedance is induced at 23 Ω;

fig. 8(b) is a schematic diagram of the NFC antenna including the FPC and the metal decoration provided in the embodiment of the present application in the case where the passive impedance is induced at 23 Ω;

fig. 9 is a schematic diagram of distribution of inductive areas of NFC antennas of different structures of different cards according to an embodiment of the present application;

fig. 10 is a circuit diagram of a dual-end NFC antenna according to an embodiment of the present disclosure;

FIG. 11 is a schematic view of a metal decoration on a remote controller;

fig. 12 is a simplified schematic diagram of a single-ended NFC antenna circuit according to an embodiment of the present application;

fig. 13 is a simplified schematic diagram of a dual-ended NFC antenna circuit according to an embodiment of the present disclosure;

fig. 14 is a schematic view of a metal decoration on a sound box.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

Fig. 3 is a schematic diagram of an NFC system according to an embodiment of the present application. As shown in fig. 3, the system includes an NFC chip 301, a matching circuit 302, and an NFC antenna 303. The NFC chip 301 is connected to an NFC antenna 303 through a matching circuit 302.

The NFC chip 302 is a short-distance high-frequency wireless communication technology, which may have a mutual communication function and a calculation capability, may implement contactless point-to-point data transmission and data exchange between electronic devices, and may be compatible with Radio Frequency Identification (RFID). In practical application, by combining the functions of an inductive card reader, an inductive card and point-to-point on an NFC single chip, identification, data exchange and the like with compatible equipment can be carried out within a short distance. The present application is not limited to this, and may be a chip produced by any manufacturer.

And the matching circuit 302 is arranged between the NFC chip 301 and the NFC antenna 303, and is used for adjusting the operating frequency of the NFC antenna 303 within the operating bandwidth range to satisfy better antenna matching, so as to improve the performance of the NFC system. .

Illustratively, in a two-terminal NFC system as shown in fig. 4, the matching circuit 302 includes two inductors and three pairs of capacitors. The two inductors and two capacitors of one of the three pairs of capacitors are respectively connected in series on two lines between the NFC chip 301 and the NFC antenna 303; and one ends of the other two pairs of capacitors are respectively connected to two ends of the capacitors connected in series, and the other ends of the capacitors are grounded.

The two inductors and the two grounding capacitors close to the inductors form a filter circuit for filtering out high-frequency signals in the electric signals sent by the NFC chip 302; the two capacitors connected in series with the inductor and the two grounded capacitors near the NFC antenna 303 form an adjusting circuit for adjusting the negative capacitance value in the matching circuit 302.

Illustratively, in the single-ended NFC system shown in fig. 5, the matching circuit 302 includes two inductors, four capacitors, and one balun. Wherein, the balun can be a small transformer.

In the circuit, two inductors are respectively arranged on two lines between the NFC chip 301 and the balun; one end of each of the four capacitors is connected to a line between the inductor and the balun, and the other end of each capacitor is grounded; the third capacitor of the four capacitors is connected in series between the third interface of the four interfaces of the balun and one end of the NFC antenna 303; one end of a fourth capacitor of the four capacitors is connected between the third capacitor and the NFC antenna 303, and the other end of the fourth capacitor is grounded; the fourth interface of the four interfaces of the balun is grounded.

Two inductors positioned between the NFC chip 301 and the balun and two grounded capacitors form a filter circuit, and are used for filtering out a high-frequency signal in an electrical signal sent by the NFC chip 302; two capacitors located between the balun and the NFC antenna 303 constitute an adjusting circuit for adjusting the negative capacitance resistance value in the matching circuit 302, and the balun is used for performing balance-unbalance conversion between the matching circuit 302 and the NFC antenna 303.

The metal decoration (metal decoration) mentioned in the embodiment of the present application may be a metal part between a camera lens and an equipment housing on an intelligent device, a metal directional keyboard of an "up/down/left/right" key on a remote controller, a metal ring on a sound box, a metal sound outlet protection ring, and the like. Generally, the sizes of the metal decorative pieces are large, and the metal decorative pieces can be connected with a chip through an FPC or a coil, so that a return path of the NFC antenna 303 is increased, and the induction area of the NFC antenna 303 is increased.

Example one

Take a metal protection frame between a camera lens and a housing on a smart phone as shown in fig. 6 as an example of a decoration.

As shown in fig. 7, in the single-ended NFC antenna circuit, the metal decoration is connected to a feed point on the PCB sequentially through a trace on the PCB and a coil on the FPC, and is connected to the matching circuit 302; the metal decoration part is grounded through another wire on the PCB. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from a coil on the FPC to a trace on the PCB and then to the metal decoration, so that the metal decoration radiates an electromagnetic field outward; the electrical signal then flows from the metal trim back to ground through another trace on the PCB.

Generally speaking, the size of the metal decoration of the camera on the mobile phone is relatively large, the longitudinal length of the metal decoration can reach 40mm, and the length of the metal decoration is far greater than that of the metal frame in fig. 1, so that the metal decoration of the camera replaces the metal frame to be used as a part of the NFC antenna 303, and the NFC performance can be improved.

In the present application, comparing the NFC antenna 303 circuit designed in fig. 7 with the existing NFC antenna 303 circuit in fig. 1, the passive impedances of the two NFC antenna circuits are first adjusted to 23 Ω, as shown in fig. 8. Fig. 8(a) shows a case where the NFC antenna 303 circuit including the FPC and the metal bezel radiates a magnetic field outward when the passive impedance is adjusted to 23 Ω, and fig. 8(b) shows a case where the NFC antenna 303 circuit including the FPC and the metal bezel radiates a magnetic field outward when the passive impedance is adjusted to 23 Ω.

Then, different cards, such as T1, T2T, T3, T3T, T4, T4A, TV, bus card, id card, etc., are respectively tested with two different mobile phones with NFC antenna 303 circuits, and the farthest distance of the induction generated by the different cards and the NFC antenna 303 on the mobile phone is detected, as shown in the following table:

table-the farthest distance for induction between different card and two different NFC antennas

According to the results of different card tests recorded in table one, compared with the mobile phone with the NFC antenna 303 circuit including the FPC and the metal frame, the distance between the mobile phone with the NFC antenna 303 circuit including the FPC and the metal decoration and different cards where the induction is generated is increased by about 7% to 31%.

In the card reading area comparison process, taking two types of cards, i.e., T4A and TV, as an example, to be respectively close to a mobile phone including different NFC antenna 303 circuits, then moving the position of the sensing chip in the card, performing a test three times, and detecting the number of times of the sensing between the card and the mobile phone at different positions, as shown in fig. 9. Fig. 9(a) is a distribution diagram of the number of times of induction generated by detection of different positions of the mobile phone, in which the card T4A is close to the NFC antenna 303 circuit including the FPC and the metal decoration, fig. 9(b) is a distribution diagram of the number of times of induction generated by detection of different positions of the mobile phone, in which the card T4A is close to the NFC antenna 303 circuit including the FPC and the metal bezel, fig. 9(c) is a distribution diagram of the number of times of induction generated by detection of different positions of the mobile phone, in which the card TV is close to the NFC antenna 303 circuit including the FPC and the metal decoration, and fig. 9(d) is a distribution diagram of the number of times of induction generated by detection of different positions of the mobile phone, in which the card TV is close to the NFC antenna 303 circuit including the FPC and the metal bezel.

Wherein, 0 in the figure indicates that the position is not successfully swiped for three times, 1 in the figure indicates that the position is successfully swiped for three times, 2 in the figure indicates that the position is successfully swiped for three times, and 3 in the figure indicates that the position is successfully swiped for three times.

The statistical test results are shown in the following table:

generating an inductive area between two different cards and two different NFC antennas

According to the results of the statistics in table two, compared with the mobile phone including the NFC antenna 303 circuit of the FPC and the metal frame, the area of induction generated between the mobile phone including the NFC antenna 303 circuit of the FPC and the metal decoration and different cards is increased by about 20%.

Therefore, in the embodiment of the application, the metal decoration of the camera in the mobile phone is designed into a part of the NFC antenna 303, compared with a metal frame of the mobile phone, the induction distance and the induction area of the NFC antenna 303 are obviously improved, the problem that the induction distance of the NFC antenna is short due to the short length of the frame of the mobile phone is solved, and meanwhile, the design pressure of other antennas is reduced due to the decoupling of the frame antennas.

As shown in fig. 10, in the dual-end NFC antenna circuit, the metal decoration is connected to the coil on the FPC through two traces on the PCB, and the coil on the FPC is connected to the feed point on the PCB and connected to the matching circuit 302. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from the coil on the FPC to the two wires on the PCB and then to the metal decoration, so that the metal decoration radiates an electromagnetic field outward; the electrical signal then flows from the metallic trim back to the feed point through the two traces on the PCB and the coil on the FPC, and back to ground on the matching circuit 302.

Compared with the double-end NFC antenna shown in the figure 2, in the embodiment of the application, the metal decoration part of the camera in the mobile phone is designed into one part of the NFC antenna 303, so that the problem that the induction distance of the NFC antenna is short due to the short length of the frame of the mobile phone is solved, meanwhile, the double-end NFC antenna is decoupled with other frame antennas, the design pressure of other antennas is reduced, and the double-end NFC antenna designed by the application does not need to increase the induction area of the NFC antenna by adding extra coils and ferrites, so that the cost is reduced.

Example two

Take the metal directional keyboard of the up/down/left/right button on the remote controller corresponding to the smart screen as shown in fig. 11 as an example.

To wisdom screen and remote controller, generally be mutually independent equipment, generally in order to make the quick connection between wisdom screen and the remote controller, can set up the NFC system in that the remote controller is inside. In the connection process, the remote controller is only required to be close to the intelligent screen sensing area, and quick connection can be achieved.

In general, the "up/down/left/right" keys on the remote control may be designed as a metal directional keypad. In order to increase the sensing distance and the sensing area of the NFC antenna 303, the metal directional keypad may be coupled to the original NFC antenna, and the NFC antenna may be designed using the metal directional keypad as a part of the NFC antenna, so as to increase the sensing distance and the sensing area of the NFC antenna 303.

As shown in fig. 12, in the single-ended NFC antenna circuit, the metal directional keypad is connected to a feed point on the PCB sequentially through a trace on the PCB and a coil on the FPC, and is connected to the matching circuit 302; the metal directional keyboard is grounded through another routing wire on the PCB. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from a coil on the FPC to a trace on the PCB and then to the metal directional keyboard, so that the metal directional keyboard radiates an electromagnetic field outward; the electrical signal then flows from the metal directional keypad back to ground through another trace on the PCB.

As shown in fig. 13, in the dual-end NFC antenna circuit, the metal directional keypad is connected to the FPC upper coil through two traces on the PCB, and the FPC upper coil is connected to a feed point on the PCB and connected to the matching circuit 302. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from the coil on the FPC to the two wires on the PCB and then to the metal directional keyboard, so that the metal directional keyboard radiates an electromagnetic field outward; the electrical signal then flows back from the metal directional keypad through two traces on the PCB and the coil on the FPC to the feed point and back to ground on the matching circuit 302.

In the above scheme of this application, compare and do not use the scheme that metal direction keyboard regarded as a part of NFC antenna 303, improve NFC antenna 303's inductive distance and increase induction area.

EXAMPLE III

A metal sound outlet protection ring on a sound box as shown in fig. 14 is taken as an example of a garnish.

Along with intelligent development, present audio amplifier adopts bluetooth and cell-phone to be connected mostly, because NFC has the security height, advantages such as data transmission is fast, can use the NFC technique when cell-phone and audio amplifier are connected, reaches quick discernment and connects.

Generally, in order to protect the speaker outlet, a metal ring is disposed on the speaker outlet or outside the speaker outlet to protect the speaker outlet from damage. In order to increase the sensing distance and the sensing area of the NFC antenna 303, the metal ring may be coupled to the original NFC antenna, and the NFC antenna may be designed by using the metal ring as a part of the NFC antenna, so as to increase the sensing distance and the sensing area of the NFC antenna 303.

For the single-ended NFC antenna circuit, referring to the schematic structural diagram shown in fig. 12, the metal ring is connected to a feed point on the PCB through a trace on the PCB and a coil on the FPC in sequence, and is connected to the matching circuit 302; the metal ring is grounded through another trace on the PCB. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from a coil on the FPC to a trace on the PCB and then to the metal ring, so that the metal ring radiates an electromagnetic field outward; the electrical signal then flows from the metal ring back to ground through another trace on the PCB.

For the double-end NFC antenna circuit, referring to the schematic structural diagram shown in fig. 13, the metal ring is connected to the FPC upper coil through two traces on the PCB, and the FPC upper coil is connected to a feed point on the PCB and connected to the matching circuit 302. When the NFC chip 301 outputs an electrical signal to a feed point on the PCB, for the NFC antenna 303, the electrical signal is transmitted from the coil on the FPC to the two wires on the PCB and then to the metal ring, so that the metal ring radiates an electromagnetic field outward; the electrical signal then flows from the metal ring back to the feed point through two traces on the PCB and the coil on the FPC, and back to ground on the matching circuit 302.

In the above scheme of the present application, compared with a scheme that does not use a metal ring as a part of NFC antenna 303, the sensing distance of NFC antenna 303 is increased and the sensing area is increased.

The present application only uses the above three products of the mobile phone, the remote controller and the sound box as examples to describe the solution to be protected in the present application, and those skilled in the art can think that the technical solution to be protected in the present application is not limited to the above three products, but can also be applied to other products, and the present application is not limited herein.

In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

Finally, the description is as follows: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. An electronic device, comprising:

a metal decoration for radiating an electromagnetic field outward when an electric signal is turned on;

the metal decorating part is connected with the FPC through the wiring of the PCB, the FPC is connected with a feed point on the PCB so as to receive an electric signal output by an NFC chip through the feed point, and the electric signal and/or an outward radiation electromagnetic field are provided for the metal decorating part through the wiring on the PCB.

2. The electronic device of claim 1, wherein the metal decoration is one or more of a metal frame of a camera, a metal directional keyboard of a remote controller, a metal ring on a sound box, and a metal sound outlet protection ring on the sound box.

3. An NFC system, comprising: an NFC chip, a matching circuit and an electronic device as claimed in claim 1 or 2.