NFC antenna

Abstract

The invention discloses an NFC antenna, which comprises a ferrite layer and a flexible circuit board layer, the flexible circuit board layer comprises a base material layer, the length of the long side of the base material layer is greater than two times of the length of the short side, and a feed area is arranged at the edge of the middle part of the base material layer; the first feed point and the second feed point are arranged in the feed area; the first antenna is arranged on the first surface and extends inwards in a surrounding manner from the second feed point along the outer edge of the first surface and the inner edge of the feed area to form a plurality of circles of coil structures, and arc-shaped transition is arranged at corners; the second antenna is arranged in the feed area and extends to the second end from the first feed point; the third antenna is arranged on the second surface; the ferrite layer comprises a hollow area exposing the first feed point and the second feed point; the NFC antenna further comprises a feeder line. Through the large-area antenna arc-shaped wiring design, after matching optimization is combined, the induction distance can be greatly increased, the induction speed can be remarkably increased, and the user experience can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of near field communication, and in particular relates to an NFC antenna. Background Art

[0002] NFC is developed based on contactless radio frequency identification (RFID) technology combined with wireless interconnection technology. It provides a very safe and fast communication method for various electronic products that are becoming more and more popular in our daily lives. Near field communication business combines near field communication technology with mobile communication technology, and realizes multiple functions such as electronic payment, identity authentication, ticketing, data exchange, anti-counterfeiting, and advertising. It is a new type of business in the field of mobile communications. Near field communication business enhances the functions of mobile phones, makes users' consumption behavior gradually move towards electronicization, and establishes a new user consumption and business model.

[0003] In order to be compatible with contactless smart cards, the NFC standard specifies a flexible gateway system, which is divided into three working modes: point-to-point communication mode, reader / writer mode, and NFC card simulation mode. With the development of the automotive industry, NFC technology in reader / writer mode is widely used in vehicle unlocking and locking operations. The NFC antenna is generally built into the rearview mirror as a reader / writer. When the digital key or card key is close to the rearview mirror, the vehicle can be locked or unlocked. The existing NFC antenna has a short reading and writing sensing distance, which can only achieve a sensing distance of about 5cm. Users need to place the key close to the NFC antenna to achieve the operation, resulting in a slow sensing speed, which is not conducive to improving the user experience. Summary of the invention

[0004] The purpose of the present application is to provide an NFC antenna to solve the technical problem that the existing NFC antenna has a short reading and writing sensing distance, resulting in a slow sensing speed, which is not conducive to improving the user experience.

[0005] In order to achieve the above object, the present application provides an NFC antenna, comprising a stacked ferrite layer and a flexible circuit board layer, wherein the flexible circuit board layer comprises:

[0006] A substrate layer, comprising a first surface facing the ferrite layer and a second surface away from the ferrite layer, the substrate layer comprising a long side extending along the x-axis direction and a short side extending along the y-axis direction, the length of the long side being greater than twice the length of the short side, and a feeding area being arranged at a middle edge of one of the long sides of the first surface;

[0007] A first feeding point and a second feeding point are arranged in the feeding area at intervals along the x-axis direction;

[0008] A first antenna is arranged on the first surface, the first antenna extends inwardly from the second feeding point along the outer edge of the first surface and the inner edge of the feeding area to the first end to form a plurality of coil structures, the first end is arranged on the inner side of the first feeding point in the y-axis direction, and an arc transition is provided at the corner of the first antenna;

[0009] A second antenna is arranged in the feeding area, and the second antenna extends from the first feeding point to a second end along the y-axis direction;

[0010] a third antenna, arranged on the second surface, the third antenna extending from a projection of the first end on the second surface to a projection of the second end on the second surface, and two ends of the third antenna being connected to the first end and the second end respectively through a connecting column penetrating through the substrate layer;

[0011] The ferrite layer includes a hollow area exposing the first feeding point and the second feeding point; and the NFC antenna also includes a feeding line connected to the first feeding point and the second feeding point respectively.

[0012] In one or more embodiments, the flexible circuit board layer further includes a backing glue layer and a release film layer, the backing glue layer is arranged on the second surface and covers the third antenna, and the release film layer is arranged on a side of the backing glue layer away from the substrate layer.

[0013] In one or more embodiments, the flexible circuit board layer further includes a nickel-plated layer arranged on surfaces of the first antenna, the second antenna, and the third antenna.

[0014] In one or more embodiments, it further includes:

[0015] a first covering film, arranged on the first surface;

[0016] The second covering film is arranged on a side of the ferrite layer away from the base material layer.

[0017] In one or more embodiments, the extended length of the long side is 114-116 mm, and the extended length of the short side is 39-41 mm.

[0018] In one or more embodiments, the first feed point and the second feed point are rectangular feed points, the distance between the first feed point and the second feed point is 1.0-1.2 mm, the extension length of the first feed point and the second feed point in the x-axis direction is 1.9-2.1 mm, and the extension length in the y-axis direction is 2-3 mm.

[0019] In one or more embodiments, the widths of the first antenna, the second antenna, and the third antenna are 1.9-2.1 mm, and in the plurality of coil structures of the first antenna, the spacing between adjacent coils is 0.45-0.55 mm.

[0020] In one or more embodiments, a fixing hole is further arranged at the edge of the substrate layer, and the first antenna is extended along the inner edge of the fixing hole.

[0021] In one or more embodiments, the first feeding point is arranged at the center of the long side of the first surface.

[0022] In one or more embodiments, the first antenna includes a two-turn coil structure.

[0023] Different from the prior art, the beneficial effects of this application are:

[0024] The first antenna, the second antenna and the third antenna of the present application form a loop, and the antenna is fed by a feeder line. Through the large-area antenna arc routing design, combined with matching optimization, the sensing distance can be greatly improved. When applied to the car rearview mirror for unlocking and locking operations of the car, the sensing distance reaches 9cm, which significantly improves the sensing speed and helps to improve the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is the experimental result diagram of the sensing distance detection of the existing NFC antenna;

[0027] Figure 2 This is a schematic diagram of the structure of an embodiment of the NFC antenna of the present application;

[0028] Figure 3 It is a schematic cross-sectional structure diagram of an embodiment of an NFC antenna of the present application;

[0029] Figure 4 This is a schematic structural diagram of an embodiment of the first surface of the substrate layer of the present application;

[0030] Figure 5 This is a schematic structural diagram of an embodiment of the second surface of the substrate layer of the present application;

[0031] Figure 6 This is a diagram of the induction distance detection experiment results of the NFC antenna of the present application.

[0032] As shown in the figure:

[0033] Ferrite layer 10; hollow area 101;

[0034] Flexible circuit board layer 20; substrate layer 201; long side 2011; short side 2012; fixing hole 2013; first surface 2014; feeding area 20141; second surface 2015; first antenna 202; arc transition 2021; first end 2022; second antenna 203; second end 2031; third antenna 204; adhesive layer 205; release film layer 206; first feeding point 207; second feeding point 208; antenna layer 209; nickel-plated layer 210;

[0035] Adhesive layer 30;

[0036] Feeder 40;

[0037] A first covering film 50;

[0038] The second cover film 60 . DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] At present, when the NFC antenna in the existing technology is used as a reader on the rearview mirror of the car, the reading and writing sensing distance is only about 5cm. Figure 1 , Figure 1 This is the experimental result diagram of the sensing distance detection of the existing NFC antenna, such as Figure 1 As shown, the existing NFC antenna is attached to the inner side of the rearview mirror cover 1. During the test, the unlocking card 3 is gradually brought closer to the rearview mirror cover 1 until the induction is successful. The result shows that when the induction is successful, the sensing distance displayed by the ruler 2 is only 5.2 cm. The shorter antenna sensing distance leads to a slower sensing speed, which is not conducive to improving the user experience.

[0041] In order to solve the above problems, the applicant has developed a new type of NFC antenna, which can achieve a sensing distance greater than 9 cm. When applied to a car rearview mirror, it can significantly improve the vehicle's operating sensing speed and help improve the user experience.

[0042] Specifically, see Figure 2 , Figure 2 It is a structural schematic diagram of an implementation scheme of an NFC antenna of the present application.

[0043] like Figure 2As shown, the NFC antenna includes a stacked ferrite layer 10 and a flexible circuit board layer 20, a first feeding point 207 and a second feeding point 208 are arranged on the flexible circuit board layer 20, and a hollow area 101 for exposing the first feeding point 207 and the second feeding point 208 is arranged on the ferrite layer 10.

[0044] The NFC antenna further includes a feeding line 40 connected to the first feeding point 207 and the second feeding point 208 respectively.

[0045] The structure is described in detail below. Figure 3 , Figure 3 It is a schematic cross-sectional structure diagram of an embodiment of the NFC antenna of the present application.

[0046] like Figure 3 As shown, in order to fix the ferrite layer 10 and the flexible circuit board layer 20 , the NFC antenna further includes an adhesive layer 30 arranged between the ferrite layer 10 and the flexible circuit board layer 20 .

[0047] The flexible circuit board layer 20 includes a substrate layer 201 , and the substrate layer 201 includes a first surface 2014 facing the ferrite layer 10 and a second surface 2015 facing away from the ferrite layer 10 .

[0048] In one embodiment, the substrate layer 201 may be PI with a thickness of 25 μm. In other embodiments, the substrate layer 201 may also be made of any material available in the art, and its thickness may be set based on actual needs, and the effects of this embodiment can be achieved.

[0049] The antenna layer 209 is arranged on the first surface 2014 and the second surface 2015 of the base material layer 201 .

[0050] In order to achieve the bonding and fixing of the NFC antenna, the flexible circuit board layer 20 further includes an adhesive layer 205 and a release film layer 206 . The adhesive layer 205 is arranged on the second surface 2015 , and the release film layer 206 is arranged on the side of the adhesive layer 205 away from the substrate layer 201 .

[0051] The antenna structure of this application is described in detail below. Figure 4 and Figure 5 , Figure 4 This is a schematic structural diagram of an embodiment of the first surface of the substrate layer of the present application. Figure 5 It is a schematic structural diagram of an embodiment of the second surface of the substrate layer of the present application.

[0052] like Figure 4 As shown, the substrate layer 201 includes a long side 2011 extending along the x-axis direction and a short side 2012 extending along the y-axis direction, and the length of the long side 2011 is greater than twice the length of the short side 2012 .

[0053] In one embodiment, the extension length of the long side 2011 may be 114-116 mm, and the extension length of the short side 2012 may be 39-41 mm. For example, the extension length of the long side 2011 may be 115 mm, and the extension length of the short side 2012 may be 40 mm.

[0054] A feeding area 20141 is arranged at the middle edge of one long side 2011 of the first surface 2014 , and the feeding area 20141 is arranged with a first feeding point 207 and a second feeding point 208 arranged at intervals along the x-axis direction.

[0055] In order to optimize the signal, in this embodiment, the first feeding point 207 is arranged at the center of the long side 2011 of the first surface 2014 .

[0056] Specifically, the first surface 2014 is arranged with a first antenna 202 and a second antenna 203. The first antenna 202 extends inward from the second feed point 208 along the outer edge of the first surface 2014 and the inner edge of the feeding area 20141 to the first end 2022 to form a two-turn coil structure. The first end 2022 is arranged on the inner side of the first feed point 207 in the y-axis direction, and an arc transition 2021 is provided at the corner of the first antenna 202.

[0057] The second antenna 203 is arranged in the feeding area 20141 , and the second antenna 203 extends from the first feeding point 207 to the second end 2031 along the y-axis direction.

[0058] In this embodiment, a fixing hole 2013 is further arranged at the edge of the substrate layer 201 , and the first antenna 202 is extended along the inner edge of the fixing hole 2013 .

[0059] It can be understood that in this embodiment, the first antenna 202 is provided with arc transitions 2021 at the corners of the first surface 2014, the inner edge of the feeding area 20141 and the inner edge of the fixing hole 2013, so as to ensure the overall arc-shaped routing.

[0060] It should be noted that in this embodiment, the first antenna 202 is a two-turn coil structure. In other embodiments, the first antenna 202 may also include coil structures of other numbers, such as three turns, four turns, etc., which can achieve the effect of this embodiment.

[0061] In addition, from the perspective facing the first surface 2014, the first antenna 202 is arranged to surround the second feed point 208 in a counterclockwise direction. In other embodiments, the first antenna 202 can also be arranged to surround in a clockwise direction, and the effect of this embodiment can be achieved.

[0062] In this embodiment, the first feed point 207 and the second feed point 208 are both rectangular feed points, which can be a gold finger structure commonly used in the art. In other embodiments, the first feed point 207 and the second feed point 208 can also be other shapes, as long as they can realize the feeding points of the coil, and can achieve the effect of this embodiment.

[0063] In one embodiment, the distance between the first feed point 207 and the second feed point 208 may be 1.0-1.2 mm, the extension length of the first feed point 207 and the second feed point 208 in the x-axis direction may be 1.9-2.1 mm, and the extension length in the y-axis direction may be 2-3 mm.

[0064] like Figure 5 As shown, the third antenna 204 extends from the projection of the first end 2022 on the second surface 2015 to the projection of the second end 2031 on the second surface 2015 , and the two ends of the third antenna 204 are respectively connected to the first end 2022 and the second end 2031 through connecting columns penetrating the substrate layer 201 .

[0065] In one implementation, the widths of the first antenna 202 , the second antenna 203 , and the third antenna 204 may be 1.9-2.1 mm, and the spacing between adjacent coils of the first antenna 202 may be 0.45-0.55 mm.

[0066] In one embodiment, the first antenna 202 , the second antenna 203 , and the third antenna 204 may be made of electrolytic copper, and the thickness may be 10-30 μm.

[0067] like Figure 3 As shown, in order to prevent the antenna from being corroded and to increase the service life, in this embodiment, a nickel-plated layer 210 is further arranged on the surface of the first antenna 202, the second antenna 203 and the third antenna 204. In one embodiment, the thickness of the nickel-plated layer 210 can be 2 to 6 μm.

[0068] Furthermore, a first covering film 50 is disposed on the first surface 2014 , and a second covering film 60 is disposed on the side of the ferrite layer 10 facing away from the substrate layer 201 .

[0069] In one embodiment, the material of the first cover film 50 and the second cover film 60 may be PI, and the thickness thereof may be 12.5 μm.

[0070] Based on the NFC antennas of the above-mentioned embodiments, the first antenna 202, the second antenna 203 and the third antenna 204 form a loop, and the antennas are fed by the feeder 40. Through the large-area arc-shaped antenna routing design, combined with matching optimization, the sensing distance can be greatly improved.

[0071] See also Figure 6 , Figure 6This is a graph showing the experimental results of the sensing distance detection of the NFC antenna of this application. Figure 6 As shown, the NFC antenna of this embodiment is attached to the inner side of the rearview mirror cover 1. During the test, the unlocking card 3 is gradually brought closer to the rearview mirror cover 1 until the induction is successful. The results show that when the induction is successful, the sensing distance displayed by the ruler 2 is close to 9 cm, which is significantly higher than Figure 1 The prior art shown, when applied as a reader / writer to the locking and unlocking of a car, can significantly increase the sensing speed and help improve the user experience.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0073] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An NFC antenna, characterized in that: The invention comprises a ferrite layer and a flexible circuit board layer which are stacked, wherein the flexible circuit board layer comprises: A substrate layer, comprising a first surface facing the ferrite layer and a second surface away from the ferrite layer, the substrate layer comprising a long side extending along the x-axis direction and a short side extending along the y-axis direction, the length of the long side being greater than twice the length of the short side, and a feeding area being arranged at a middle edge of one of the long sides of the first surface; A first feeding point and a second feeding point are arranged in the feeding area at intervals along the x-axis direction; A first antenna is arranged on the first surface, the first antenna extends inwardly from the second feeding point along the outer edge of the first surface and the inner edge of the feeding area to the first end to form a plurality of coil structures, the first end is arranged on the inner side of the first feeding point in the y-axis direction, and an arc transition is provided at the corner of the first antenna; A second antenna is arranged in the feeding area, and the second antenna extends from the first feeding point to a second end along the y-axis direction; a third antenna, arranged on the second surface, the third antenna extending from a projection of the first end on the second surface to a projection of the second end on the second surface, and two ends of the third antenna being connected to the first end and the second end respectively through a connecting column penetrating through the substrate layer; The ferrite layer includes a hollow area exposing the first feeding point and the second feeding point; and the NFC antenna also includes a feeding line connected to the first feeding point and the second feeding point respectively.

2. The NFC antenna according to claim 1, characterized in that: The flexible circuit board layer further includes a back glue layer and a release film layer. The back glue layer is arranged on the second surface and covers the third antenna. The release film layer is arranged on a side of the back glue layer away from the substrate layer.

3. The NFC antenna according to claim 1, characterized in that: The flexible circuit board layer further includes a nickel-plated layer arranged on the surfaces of the first antenna, the second antenna and the third antenna.

4. The NFC antenna according to claim 1, characterized in that: Also includes: a first covering film, arranged on the first surface; The second covering film is arranged on a side of the ferrite layer away from the base material layer.

5. The NFC antenna according to claim 1, characterized in that: The extended length of the long side is 114-116 mm, and the extended length of the short side is 39-41 mm.

6. The NFC antenna according to claim 1, characterized in that: The first feed point and the second feed point are rectangular feed points, the distance between the first feed point and the second feed point is 1.0-1.2 mm, the extension length of the first feed point and the second feed point in the x-axis direction is 1.9-2.1 mm, and the extension length in the y-axis direction is 2-3 mm.

7. The NFC antenna according to claim 1, characterized in that: The widths of the first antenna, the second antenna and the third antenna are 1.9-2.1 mm. In the coil structure of the first antenna, the spacing between adjacent coils is 0.45-0.55 mm.

8. The NFC antenna according to claim 1, characterized in that: A fixing hole is also arranged at the edge of the substrate layer, and the first antenna is extended along the inner edge of the fixing hole.

9. The NFC antenna according to claim 1, characterized in that: The first feeding point is arranged at the center of the long side of the first surface.

10. The NFC antenna according to claim 1, characterized in that: The first antenna includes a two-turn coil structure.

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