A flexible circuit board, display device

Abstract

The present disclosure discloses a flexible circuit board and a display device, the flexible circuit board comprising: a plurality of binding pins for binding with a display panel, the plurality of binding pins comprising impedance test pins; an antenna coil comprising two metal wires and two impedance test pins, the metal wires being electrically connected between the impedance test pins and a near field communication module; wherein, after the plurality of binding pins are bound with the display panel, the two impedance test pins are electrically connected through a wire in the display panel.

Description

Technical Field

[0001] This disclosure relates to the field of near-field communication, and more particularly to a flexible circuit board and a display device. Background Technology

[0002] Currently, mobile phones and other terminal products are becoming increasingly thinner and lighter. In this context, the performance and selection of antennas are becoming more and more limited. Many terminal products have chosen to abandon the Near Field Communication (NFC) function due to insufficient internal space.

[0003] However, NFC functionality is widely used in end products, such as near-field payments and face-to-face friend adding. Abandoning NFC functionality would reduce the user experience.

[0004] Therefore, how to reduce the space occupied by NFC antennas has become a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This disclosure provides a flexible circuit board and a display device to solve the above-mentioned technical problems.

[0006] In a first aspect, to solve the above-mentioned technical problems, embodiments of this disclosure provide a flexible circuit board, comprising: Multiple bonding pins for bonding to a display panel, including an impedance test pin; The antenna coil includes two metal wires and two impedance test pins. The metal wires are electrically connected between the impedance test pins and the near-field communication module. When the plurality of bonding pins are bonded to the display panel, the two impedance test pins are electrically connected through wires in the display panel.

[0007] In one possible implementation, one of the two metal wires is arranged in a spiral, and the other metal wire is located outside the spiral and partially surrounds the spiral.

[0008] In one possible implementation, the spiral is a square spiral, and the other metal connecting line is a broken line that partially encloses the square spiral; Alternatively, the spiral may be a circular spiral, and the other metal connecting line may be an arc that partially encloses the circular spiral.

[0009] One possible implementation, the metal interconnect includes: Multiple sub-metal wires; A metal jumper wire, which is electrically connected to two adjacent sub-metal wires.

[0010] In one possible implementation, the flexible circuit board further includes: The first substrate layer is disposed near the display panel, the metal interconnect is disposed on any surface of the first substrate layer, and there is no whole metal layer on the side of the first substrate layer facing away from the display panel. At least one second substrate layer is stacked on the side of the first substrate layer away from the display panel. The plurality of bonding pins are disposed on one side surface of the second substrate layer, and the area of ​​the second substrate layer with the plurality of bonding pins corresponding to the bonding pins does not overlap with the orthographic projection of the at least one second substrate layer near the plurality of bonding pins.

[0011] In one possible implementation, the flexible circuit board further includes: A connection terminal is disposed on the surface of the second substrate layer that is furthest from the first substrate layer in the at least one second substrate layer, and the connection terminal is used to electrically connect to the near-field communication module. When the metal wire is disposed on the surface of the first substrate layer away from the second substrate layer, the connection end is electrically connected to the antenna coil through a connection hole penetrating at least one second substrate layer and the first substrate layer. When the metal wire is disposed on the side surface of the first substrate layer near the second substrate layer, the connection end is electrically connected to the antenna coil through a connection hole penetrating the at least one second substrate layer.

[0012] In one possible implementation, the flexible circuit board further includes: Devices and traces connecting the devices to the bonding pins; The device and the connection terminal are disposed on the same layer, and the traces are disposed on the surface of any second substrate layer.

[0013] In one possible implementation, the flexible circuit board further includes: An anti-electromagnetic interference layer is disposed on the side surface of the first substrate layer that is closer to the display panel; the anti-electromagnetic interference layer and the metal interconnection do not overlap in the orthographic projection of the first substrate layer.

[0014] In one possible implementation, when the metal interconnect is disposed on the side surface of the first substrate layer near the display panel, the electromagnetic interference shielding layer covers the metal interconnect.

[0015] In one possible implementation, in at least one second substrate layer closest to the first substrate layer, the metal interconnects do not overlap with the traces and devices on the surface of the corresponding second substrate layer within the orthographic projection area of ​​the corresponding second substrate layer.

[0016] In one possible implementation, the flexible circuit board further includes: The test terminal is disposed on the surface of the first substrate layer away from the second substrate layer. The test terminal is electrically connected to the end of the metal connection near the near-field communication module. The test terminal is used to connect an impedance testing tool.

[0017] Secondly, embodiments of this disclosure provide a display device, including: Display panel, flexible circuit board as described in the first aspect, and near-field communication module; The flexible circuit board is located on the back side of the display surface of the display panel, and multiple bonding pins in the flexible circuit board are bonded to the display surface of the display panel; The near-field communication module is electrically connected to the antenna coil in the flexible circuit board.

[0018] In one possible implementation, the display device further includes: An ultra-clean foam SCF composite film is located between the back of the display panel and the flexible circuit board; the SCF composite film includes a heat dissipation layer, a buffer layer and an adhesive layer stacked together, the adhesive layer being fixed to the back of the display panel; the heat dissipation layer has a perforated area, the orthographic projection of the perforated area on the flexible circuit board covering the metal connection line of the antenna coil.

[0019] In one possible implementation, the display device further includes insulating adhesive filled in the perforated area of ​​the heat dissipation layer.

[0020] In one possible implementation, the antenna coil is connected to the near-field communication module via a spring. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the antenna configuration in related technologies; Figure 2 This is a schematic diagram of the structure of a flexible circuit board provided in an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the connection of the antenna coil provided in an embodiment of the present disclosure; Figures 4-6 This is a schematic diagram of the structure of an antenna coil provided in an embodiment of the present disclosure; Figures 7-9 A cross-sectional view of a flexible circuit board in the thickness direction provided in an embodiment of this disclosure; Figure 10 This is a schematic diagram of the structure of two metal wires connecting the antenna coil provided in an embodiment of the present disclosure; Figure 11 This is a schematic diagram of another antenna coil structure provided in an embodiment of the present disclosure; Figure 12 This is a schematic diagram of another antenna coil structure provided in an embodiment of the present disclosure; Figure 13 , Figure 14 A cross-sectional view in the thickness direction of another flexible circuit board provided in an embodiment of this disclosure; Figure 15 A cross-sectional view of another flexible circuit board provided in an embodiment of this disclosure; Figure 16 , Figure 17 This is a schematic diagram of another flexible circuit board structure provided in an embodiment of the present disclosure; Figure 18 This is a schematic diagram of another flexible circuit board structure provided in an embodiment of the present disclosure; Figure 19 This is a schematic diagram of another flexible circuit board structure provided in an embodiment of the present disclosure; Figure 20 This is a schematic diagram of the structure of a display device provided in an embodiment of the present disclosure; Figure 21 This is another schematic diagram of the structure of a display device provided in an embodiment of this disclosure; Figure 22 This is another schematic diagram of the structure of a display device provided in an embodiment of this disclosure.

[0022] Bonding pin 1, impedance test pin 12, antenna coil 2, metal wire 21, first end 21a of metal wire 21, second end 21b of metal wire 21, first substrate layer 3, second substrate layer 4, connection end 5, connection hole 6, device 7, trace 8, electromagnetic interference suppression layer 9. Display panel 100, flexible circuit board 200, near-field communication module 300, and cutout area B. Detailed Implementation

[0023] This disclosure provides a flexible circuit board and a display device to solve the technical problem of large space occupation by NFC antennas.

[0024] To make the above-described objects, features, and advantages of this disclosure more apparent and understandable, the disclosure will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the disclosure more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction as described in this disclosure are illustrative of the accompanying drawings, but changes may be made as needed, and all such changes are included within the scope of protection of this disclosure. The accompanying drawings of this disclosure are for illustrative purposes only and do not represent actual scale.

[0025] It should be noted that specific details are set forth in the following description to provide a full understanding of this disclosure. However, this disclosure can be implemented in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this disclosure. Therefore, this disclosure is not limited to the specific embodiments disclosed below. The following description is a preferred embodiment for carrying out this application; however, the description is for the purpose of illustrating the general principles of this application and is not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0026] In related technologies, antennas in terminal products are typically designed using Laser-Direct-Structured (LDS) technology. NFC communication distance is generally around 10cm, operating at a frequency of 13.5MHz, with a maximum transmission rate of 424Kbit. NFC antennas are generally designed as closed coils, radiating signals outwards through inductance generated by changes in current within the closed coil. For example... Figure 1 The diagram shows the shape of an antenna in related technologies. Figure 1 One end of the antenna is used as a feed signal, and the other end is used as a ground point and electrically connected to the communication module.

[0027] The following description, in conjunction with the accompanying drawings, details an embodiment of the flexible circuit board and display device provided in this disclosure.

[0028] Please see Figure 2 This is a schematic diagram of a flexible circuit board provided in an embodiment of the present disclosure. The flexible circuit board includes: Multiple bonding pins 1, multiple bonding pins 1 are used for connection with the display panel ( Figure 2 (Not shown in the image) Bonding, including an impedance test pin 12 among the multiple bonding pins 1; typically the impedance test pin 12 is located at the edge of the multiple bonding pins 1.

[0029] In related technologies, after multiple bonding pins 1 are bonded to the display panel, the two impedance test pins 12 will be in a conductive state. In this way, during the production process, the connecting wires led out from the two impedance test pins 12 can be electrically connected to the impedance testing tool to measure the impedance of the bonding pins 1 after the display panel is bonded.

[0030] It is necessary to understand that Figure 2 Although the two impedance test pins 12 are numbered differently from the bonding pin 1, this is for ease of explanation. In fact, the impedance test pin 12 is also one of the multiple bonding pins 1.

[0031] Antenna coil 2 includes two metal wires 21 and two impedance test pins 12; the metal wires 21 are electrically connected to the impedance test pins 12 and the near-field communication module. Figure 2 Between (not shown); wherein, after multiple bonding pins 1 are bonded to the display panel, two impedance test pins 12 are electrically connected through wires in the display panel. After multiple bonding pins 1 are bonded to the display panel, wires in the display panel are connected between the two impedance test pins 12, so that the two impedance test pins 12 are electrically connected through wires in the display panel.

[0032] In the embodiments provided in this disclosure, an antenna coil 2 is constructed by utilizing the two impedance test pins 12 and their connecting lines (i.e., metal wires 21) used in related technologies to measure the impedance of the bonding pin 1, as well as the circuit formed after the bonding pin 1 is bonded to the display panel. This allows the circuit for measuring the impedance of the bonding pin 1 to be reused as the antenna coil 2 of the near-field communication module, thus eliminating the need for additional space to set up the antenna coil 2. This achieves the technical effect of saving space on the flexible circuit board while retaining the near-field communication function. Furthermore, since the antenna coil 2 reuses the impedance test circuit of the bonding pin 1, there is no need to add additional materials or space to separately set up the antenna coil 2, thereby effectively saving costs.

[0033] Please see Figure 3 This is a schematic diagram of the connection of the antenna coil provided in an embodiment of this disclosure.

[0034] The first end 21a of the metal connection 21 is electrically connected to the impedance test pin 12, and the second end 21b of the metal connection 21 is connected to the near-field communication module. Figure 3 Electrical connection (not shown in the image).

[0035] It is important to understand that the near-field communication module has two terminals that are electrically connected to the second ends of two metal wires, and should not be interpreted as the near-field communication module having only one terminal.

[0036] Please see Figures 4-6 This is a schematic diagram of the structure of an antenna coil provided in an embodiment of the present disclosure. The antenna coil 2 has two metal connecting wires 21, one of which is arranged in a spiral, and the other is located outside the spiral and partially surrounds the spiral.

[0037] like Figure 4 and Figure 5 As shown, the metal connecting line 21, which is set as a spiral, is a square spiral, and the other metal connecting line 21 is a broken line that semi-encloses the square spiral; the square spiral can be Figure 4 The rectangular spiral shown can also be as follows: Figure 5 The square spiral shown.

[0038] like Figure 6 As shown, the metal connecting line 21, which is set as a spiral, is a circular spiral, and the other metal connecting line 21 is an arc that semi-encloses the circular spiral.

[0039] In the embodiments provided in this disclosure, one metal wire is set as a square spiral or a circular spiral, and the other is set as a broken line that partially surrounds the square spiral or an arc that partially surrounds the circular spiral. This allows the metal connection 21 of the antenna coil 2 to adapt to the shape of the remaining space in the flexible circuit board, thereby improving the success rate of setting the antenna coil 2.

[0040] Please see Figures 7-9 A cross-sectional view in the thickness direction of a flexible circuit board provided in an embodiment of this disclosure. The flexible circuit board further includes: The first substrate layer 3 is disposed near the display panel, and the metal interconnect 21 is disposed on any surface of the first substrate layer 3, with no solid metal layer on the side of the first substrate layer 3 facing away from the display panel; for example Figure 7 and Figure 9 As shown, the metal interconnect 21 can be disposed on the surface of the first substrate layer 3 away from the second substrate layer 4, in which case no full metal layer is disposed on the surface of the first substrate layer 3 away from the display panel. Alternatively, it can be disposed on the surface of the first substrate layer 3 closer to the second substrate layer 4. In the circuit board manufacturing industry, a protective layer is usually disposed on the side of the first metal interconnect 21 away from the first substrate layer 3 to prevent physical breakage of the metal interconnect 21 and other interconnects on the same layer as the metal interconnect 21, and to protect the shape of the circuit. For example, the protective layer can be an acrylic oligomer (commonly known as green oil).

[0041] At least one second substrate layer 4 is stacked on the side of the first substrate layer 3 away from the display panel. A plurality of bonding pins 1 are disposed on one side surface of the second substrate layer 4, and the area of ​​the second substrate layer 4 with the plurality of bonding pins 1 corresponding to the bonding pins 1 does not overlap with the orthographic projection of the at least one second substrate layer 4 near the plurality of bonding pins.

[0042] like Figure 7 and8 As shown, the multiple bonding pins 1 can be disposed on any surface of the second substrate layer 4 (usually referred to as the top substrate layer) that is furthest from the first substrate layer 3, or as shown in the figure. Figure 9 The multiple bonding pins 1 are set on any surface of one of the second substrate layers 4 between the first substrate layer 3 and the second substrate layer 4 furthest from the first substrate layer 3. Specifically, the bonding pins 1 can be set on which side of which second substrate layer 4, depending on the bonding area of ​​the display panel.

[0043] Multiple bonding pins 1 correspond to areas in the top substrate layer, such as Figure 8 As shown, the orthographic projections of the remaining second substrate layer 4 and the first substrate layer 3 do not overlap; as Figure 9 As shown, it can also be applied only to the substrate layer near the multiple bonding pins 1 ( Figure 9 The middle layer consists of the second substrate layer 4 and the first substrate layer 3, which are close to the surface where the multiple pins are located. This allows the second substrate layer 4, where the multiple bonding pins 1 are located, to be supported by the second substrate layer 4 that is away from the multiple pins, thereby improving the toughness of the area where the multiple bonding pins 1 are located and thus improving its service life.

[0044] In the embodiments provided in this disclosure, by placing the metal connection 21 of the antenna coil 2 on the surface of the first substrate layer 3 close to the display panel, the signal radiation direction of the antenna coil 2 can be mainly directed towards one side of the display panel, thereby reducing the interference of the antenna coil 2 on the circuit away from the display panel. Furthermore, by placing multiple bonding pins 1 on one side surface of a second substrate layer 4, and ensuring that the area of ​​the second substrate layer 4 with multiple bonding pins 1 corresponding to the bonding pins 1 does not overlap with the orthographic projection of the other second substrate layers 4 and the first substrate layer 3, the multiple pins can be freely set according to the position of the bonding area of ​​the display panel.

[0045] Please see Figure 10 This is a schematic diagram of the structure of two metal connecting wires in an antenna coil provided in an embodiment of this disclosure. The two metal connecting wires 21 in the antenna coil 2 can be arranged in the same layer (e.g., Figures 2-6 (As shown), or as... Figure 10 The heterogeneous layer setup shown is in Figure 10 The two metal lines 21 are set with different line types to indicate that they are located in different layers. That is, one metal line 21 is set on the surface of the first substrate layer 3 near the display panel, and the other metal line 21 is set on the surface of the first substrate layer 3 away from the display panel.

[0046] Please see Figure 11This is a schematic diagram of another antenna coil structure provided in an embodiment of the present disclosure. The metal connection 21 of the antenna coil 2 includes at least one sub-metal line. When the metal connection 21 includes only one sub-metal line, this sub-metal line is the corresponding metal connection 21; when the metal connection 21 includes multiple sub-metal lines, some sub-metal connections 21 can be arranged in different layers, i.e., as shown in the diagram. Figure 11 As shown, the sub-metal wires shown by solid lines and dashed lines in the metal interconnect 21, which is configured as a square spiral, are located on different surfaces of the first substrate layer 3. Adjacent sub-metal wires can be electrically connected through connecting holes penetrating the first substrate layer 3. If the sub-metal wires in the metal interconnect 21 are arranged in the same layer, they can be electrically connected to the corresponding two sub-metal wires through jumpers arranged in other substrate layers, such as the second substrate layer 4 adjacent to the first substrate layer 3.

[0047] Please see Figure 12 This is a schematic diagram of another antenna coil structure provided in an embodiment of the present disclosure. When the metal connection 21 includes multiple sub-metal lines, the metal connection 21 further includes: Metal jumper wires are electrically connected to two adjacent sub-metal wires.

[0048] like Figure 12 In the metal interconnect 21, which is set as a square spiral, two sub-metal wires are arranged in the same layer, and the metal jumper is arranged in a different layer from the two sub-metal wires. The metal jumper and the two sub-metal wires are electrically connected through a connecting hole that penetrates the first substrate layer 3.

[0049] Please see Figure 13 and Figure 14 A cross-sectional view in the thickness direction of another flexible circuit board provided in an embodiment of this disclosure. The flexible circuit board further includes: The connection terminal 5 is disposed on the surface of at least one second substrate layer 4 on the side of the second substrate layer 4 furthest from the first substrate layer 3, and is used for electrical connection with the near-field communication module. Since the antenna coil 2 has two ends, there are two corresponding connection terminals 5. These two connection terminals 5 are respectively electrically connected to the ends of the two metal wires 21 of the antenna coil 2 furthest from the bonding pin 1 (i.e., the second end 21b of the metal wires 21). Before the near-field communication module is connected, the connection terminal 5 can also be reused as a test terminal of an impedance testing tool to connect to the impedance testing tool for impedance testing of the bonding pin 1.

[0050] When the metal wire 21 is disposed on the side surface of the first substrate layer 3 away from the second substrate layer 4, the connection end 5 is electrically connected to the antenna coil 2 through the connection hole 6 that penetrates all the second substrate layers 4 and the first substrate layer 3. When the metal wire 21 is disposed on the surface of the first substrate layer 3 near the second substrate layer 4, the connection end 5 is electrically connected to the antenna coil 2 through the connection hole 6 that penetrates all the second substrate layers 4. The connection end 5 is electrically connected to the second end 21b of the corresponding metal wire 21 through the connection hole 6.

[0051] It is important to understand that, in Figure 13 and Figure 14 In the cross-sectional view, because the two metal connecting lines 21 overlap, therefore... Figure 13 and Figure 14 At first glance, it appears that the two connecting holes 6 are connected to a single metal wire 21, but in reality, the two connecting holes 6 are connected to different metal wires 21.

[0052] In the embodiments provided in this disclosure, by placing the connection end 5 on the surface of the second substrate layer 4, which is furthest from the first substrate layer 3, away from the first substrate layer 3, it is convenient to connect to the near-field communication module outside the flexible circuit board. By connecting the second end 21b of the metal wire 21 to the connection end 5 through the connection hole 6, the metal wire 21 of the antenna coil 2 can be placed on the first substrate layer 3, which is different from the second substrate layer 4 where the connection end 5 is located, which is convenient for wiring the metal wire 21.

[0053] Please see Figure 15 This is a cross-sectional view of another flexible circuit board provided in an embodiment of the present disclosure, the flexible circuit board further comprising: Device 7 and the trace 8 connecting device 7 to the bonding pin 1; Device 7 is disposed on the same layer as connection terminal 5, and trace 8 is disposed on the surface of any second substrate layer 4.

[0054] If device 7 and bonding pin 1 are on the same layer, the trace 8 connecting device 7 and bonding pin 1 can be on the same layer as device 7 and bonding pin 1. If device 7 and bonding pin 1 are on different layers, the trace 8 connecting device 7 and bonding pin 1 can be on the same layer as device 7 or bonding pin 1, and connected to the corresponding device 7 or bonding pin 1 through corresponding connection holes. Of course, some traces 8 can be on the same layer as device 7, and other traces 8 can be on the same layer as bonding pin 1, or the trace 8 can be placed on other surfaces of the second substrate layer 4 between the surface where bonding pin 1 is located and the surface where device 7 is located. There are no specific limitations. This can increase the freedom of routing the trace 8 and facilitate flexible routing according to actual needs.

[0055] Figure 15 The connection relationship between trace 8, device 7, and bonding pin 1 is not shown; it is only schematically illustrating the positions of device 7 and bonding trace.

[0056] In the embodiments provided in this disclosure, by setting the device 7 and the connection terminal 5 on the same layer, that is, by setting the device 7 on the surface of the second substrate layer 4 furthest from the first substrate layer 3, it is convenient to arrange the device 7 and the trace 8. And by setting the trace 8 connecting the device 7 and the bonding pin 1 on any of the second substrate layers 4, it is convenient to flexibly route the trace 8 connecting the device 7 and the bonding pin 1 according to actual needs.

[0057] Please see Figure 16 and Figure 17 A schematic diagram of another flexible circuit board provided in an embodiment of this disclosure. The flexible circuit board further includes: An electromagnetic interference (EMI) layer 9 is disposed on the surface of the first substrate layer 3 closest to the display panel. The EMI layer 9 and the metal interconnect 21 do not overlap in their orthographic projections on the first substrate layer 3. The EMI layer 9 is a metal layer, such as a layer of copper.

[0058] like Figure 16 As shown, when the metal interconnect 21 is disposed on the side surface of the first substrate layer 3 away from the display panel, the electromagnetic interference layer 9 can be directly disposed on the side surface of the first substrate layer 3 close to the display panel.

[0059] like Figure 17 As shown, when the metal interconnect 21 is disposed on the surface of the first substrate layer 3 near the display panel, the electromagnetic interference suppression layer 9 covers the metal interconnect 21. If the two metal interconnects 21 of the antenna coil 2 are disposed on the two surfaces of the first substrate layer 3 respectively, the electromagnetic interference suppression layer 9 covers the metal interconnect 21 disposed on the side of the first substrate layer 3 near the display panel.

[0060] It should be understood that when the electromagnetic interference suppression layer 9 and the metal connection 21 are located on the same side of the first substrate layer 3, an insulating layer is still provided between the electromagnetic interference suppression layer 9 and the metal connection 21. Similarly, when the first substrate layer 3 and the adjacent second substrate layer 4 are adjacent to each other, if conductive components such as metal traces or metal layers are provided on both surfaces, an insulating layer must be provided between them.

[0061] In the embodiments provided in this disclosure, when a metal interconnect 21 is provided on the side surface of the first substrate layer 3 near the display panel, or on the side surface of the first substrate layer 3 near the display panel, the electromagnetic interference layer 9 covers the corresponding metal interconnect 21, and the orthogonal projections of the electromagnetic interference layer 9 and the metal interconnect on the first substrate layer do not overlap, which can prevent the signals of the antenna coil 2 and the devices 7 and circuits in the second substrate layer 4 from interfering with each other, thereby improving the reliability of the flexible circuit board.

[0062] Please see Figure 18This is a schematic diagram of another flexible circuit board structure provided in an embodiment of this disclosure. When a trace 8 is also provided on the second substrate layer 4 where the electromagnetic interference suppression layer 9 is provided, the electromagnetic interference suppression layer 9 is provided on the surface of the second substrate layer 4 that is close to the first substrate layer 3, and the trace 8 and the electromagnetic interference suppression layer 9 are disposed on different layers; in this way, the signal of the trace 8 can be shielded by the electromagnetic interference suppression layer 9, preventing electromagnetic interference to the metal connection 21 of the antenna coil 2, and improving the accuracy of the radiated signal when the antenna coil 2 is working.

[0063] When no trace 8 is provided on the second substrate layer 4 where the electromagnetic interference suppression layer 9 is provided, the electromagnetic interference suppression layer 9 is provided on any surface of the corresponding second substrate layer 4.

[0064] In the embodiments provided in this disclosure, whether the second substrate layer 4 with the electromagnetic interference suppression layer 9 is also provided with a trace 8, in which case the electromagnetic interference suppression layer 9 is provided on the surface of the second substrate layer 4 that is close to the first substrate layer 3, and the trace 8 and the electromagnetic interference suppression layer 9 are provided in different layers; or when the second substrate layer 4 with the electromagnetic interference suppression layer 9 is not provided with a trace 8, in which case the electromagnetic interference suppression layer 9 is provided on any surface of the second substrate layer 4, the electromagnetic interference suppression layer 9 can be provided between the layer where the trace 8 is located and the layer where the metal interconnect 21 is located, to prevent the two from interfering with each other.

[0065] Please see Figure 19 This is a schematic diagram of another flexible circuit board structure provided in an embodiment of the present disclosure. In at least one second substrate layer 4 closest to the first substrate layer 3, the metal interconnect 21 does not overlap with the traces 8 and devices 7 on the surface of the corresponding second substrate layer 4 in the orthographic projection area of ​​the corresponding second substrate layer 4.

[0066] like Figure 19 As shown, in the three second substrate layers 4 closest to the first substrate layer 3, the metal interconnect 21 does not overlap with the trace 8 on the surface of the corresponding second substrate layer 4 in the orthographic projection area of ​​these three second substrate layers 4. If the three second substrate layers 4 include the second substrate layer 4 farthest from the first substrate layer 3, then the metal interconnect 21 does not overlap with the trace 8 and the device 7 on the surface of the corresponding second substrate layer 4 in the orthographic projection area of ​​the second substrate layer 4 farthest from the first substrate layer 3.

[0067] In one possible implementation, the flexible circuit board further includes: The test end is located on the surface of the first substrate layer 3 away from the second substrate layer 4. The test end is electrically connected to the end of the metal connection 21 near the near-field communication module. The test end is used to connect an impedance testing tool.

[0068] By providing a dedicated test terminal for the impedance testing tool, it is easy to test the impedance of the bonding pin 1.

[0069] Based on the same inventive concept, this disclosure provides a display device, the structural schematic diagram of which is shown below. Figure 20 As shown, the display device includes: Display panel 100, flexible circuit board 200 as described above, and near field communication module 300; The flexible circuit board 200 is located on the back of the display surface of the display panel 100, and multiple bonding pins in the flexible circuit board are bonded to the display surface of the display panel 100. The near-field communication module 300 is electrically connected to the antenna coil in the flexible circuit board 200.

[0070] In the embodiments provided in this disclosure, by placing the side of the flexible circuit board 200 with the antenna coil close to the display panel 100, the signal transmitted by the antenna coil can be transmitted in the direction toward the display panel 100, instead of being transmitted from the side away from the display panel 100 like other communication modules. This reduces mutual interference with other communication modules. Furthermore, since the relevant control circuits of the display panel 100 are usually located on its back, placing the side of the flexible circuit board 200 with the antenna coil close to the display panel 100 can reduce interference to the relevant control circuits of the display panel 100.

[0071] Please see Figure 21 This is another schematic diagram of the structure of a display device provided in an embodiment of this disclosure.

[0072] The display device also includes: An ultra-clean foam SCF composite film is located between the back of the display panel 100 and the flexible circuit board 200. The SCF composite film includes a heat dissipation layer, a buffer layer, and an adhesive layer stacked together. The adhesive layer is fixed to the back of the display panel 100. The heat dissipation layer has a perforated area B, and the orthogonal projection of the perforated area B on the flexible circuit board 200 covers the metal connection wire of the antenna coil. The material of the heat dissipation layer can be copper foil.

[0073] A perforated area B is provided in the heat dissipation layer of the SCF composite film, so that the orthogonal projection of the perforated area B on the flexible circuit board 200 covers the metal connection line of the antenna coil. This can prevent the heat dissipation layer of the SCF composite film from shielding the signal emitted by the antenna coil, allowing the signal of the antenna coil to be emitted smoothly from the side facing the display panel 100.

[0074] Please see Figure 22 This is another schematic diagram of the structure of a display device provided in an embodiment of this disclosure.

[0075] The display device also includes insulating adhesive filled in the perforated area B of the heat dissipation layer.

[0076] By filling the perforated area B of the heat dissipation layer with insulating glue, the signal emitted by the antenna coil can pass smoothly through the perforated area B of the heat dissipation layer, and the heat dissipation layer that should have been removed from the perforated area B can be filled in, making the flexible circuit board 200 and the SCF composite film adhere more firmly.

[0077] Please continue reading Figures 20-22 The antenna coil can be connected to the near-field communication module 300 via a spring clip. This allows for a better connection between the antenna coil and the near-field communication module 300. Since the antenna coil is a test circuit with multiplexed test-bonded pins, it effectively reduces costs.

[0078] In the embodiments provided in this disclosure, the near field communication module 300 may be a near-field communication (NFC) module.

[0079] It is important to understand that, in Figures 20-22 In the diagram, the two metal wires connecting the antenna coil are shown with different filling patterns for easier viewing. However, in actual applications, the two metal wires of the antenna coil do not touch, and one cannot assume that they are in contact based solely on the diagram.

[0080] This display device can be used for devices that require near-field communication (NFC) functionality, such as mobile phones, tablets, smartwatches, and smart bracelets.

[0081] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0082] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A flexible circuit board, wherein, include: Multiple bonding pins for bonding to a display panel, including an impedance test pin; The antenna coil includes two metal wires and two impedance test pins, the metal wires being electrically connected between the impedance test pins and the near-field communication module; wherein, when the plurality of bonding pins are bonded to the display panel, the two impedance test pins are electrically connected through wires in the display panel; The flexible circuit board further includes: The first substrate layer is disposed near the display panel, the metal interconnect is disposed on any surface of the first substrate layer, and there is no whole metal layer on the side of the first substrate layer facing away from the display panel. At least one second substrate layer is stacked on the side of the first substrate layer away from the display panel. The plurality of bonding pins are disposed on one side surface of the second substrate layer, and the area of ​​the second substrate layer with the plurality of bonding pins corresponding to the bonding pins does not overlap with the orthographic projection of the at least one second substrate layer near the plurality of bonding pins.

2. The flexible circuit board as described in claim 1, wherein, Of the two metal connecting lines, one is arranged in a spiral, and the other is located outside the spiral and partially surrounds it.

3. The flexible circuit board as described in claim 2, wherein, The spiral is a square spiral, and the other metal connecting line is a broken line that partially surrounds the square spiral; Alternatively, the spiral may be a circular spiral, and the other metal connecting line may be an arc that partially encloses the circular spiral.

4. The flexible circuit board according to any one of claims 1-3, wherein, The metal interconnect includes: Multiple sub-metal wires; A metal jumper wire, which is electrically connected to two adjacent sub-metal wires.

5. The flexible circuit board as described in claim 1, wherein, The flexible circuit board also includes: A connection terminal is disposed on the surface of the second substrate layer that is furthest from the first substrate layer in the at least one second substrate layer, and the connection terminal is used to electrically connect to the near-field communication module. When the metal wire is disposed on the surface of the first substrate layer away from the second substrate layer, the connection end is electrically connected to the antenna coil through a connection hole penetrating at least one second substrate layer and the first substrate layer. When the metal wire is disposed on the side surface of the first substrate layer near the second substrate layer, the connection end is electrically connected to the antenna coil through a connection hole penetrating the at least one second substrate layer.

6. The flexible circuit board as described in claim 5, wherein, The flexible circuit board further includes: Devices and traces connecting the devices to the bonding pins; The device and the connection terminal are disposed on the same layer, and the traces are disposed on the surface of any second substrate layer.

7. The flexible circuit board as described in claim 6, wherein, The flexible circuit board further includes: An anti-electromagnetic interference layer is disposed on the side surface of the first substrate layer that is closer to the display panel; the anti-electromagnetic interference layer and the metal interconnection do not overlap in the orthographic projection of the first substrate layer.

8. The flexible circuit board as described in claim 7, wherein, When the metal interconnect is disposed on the side surface of the first substrate layer near the display panel, the electromagnetic interference shielding layer covers the metal interconnect.

9. The flexible circuit board according to any one of claims 5-8, wherein, In at least one second substrate layer closest to the first substrate layer, the metal interconnects do not overlap with the traces and devices on the surface of the corresponding second substrate layer within the orthographic projection area of ​​the corresponding second substrate layer.

10. The flexible circuit board according to any one of claims 5-8, wherein, The flexible circuit board also includes: The test terminal is disposed on the surface of the first substrate layer away from the second substrate layer. The test terminal is electrically connected to the end of the metal connection near the near-field communication module. The test terminal is used to connect an impedance testing tool.

11. A display device, wherein, include: Display panel, flexible circuit board as described in any one of claims 1-10, and near-field communication module; The flexible circuit board is located on the back side of the display surface of the display panel, and multiple bonding pins in the flexible circuit board are bonded to the display surface of the display panel; The near-field communication module is electrically connected to the antenna coil in the flexible circuit board.

12. The display device as claimed in claim 11, wherein, Also includes: An ultra-clean foam SCF composite film is located between the back of the display panel and the flexible circuit board; The SCF composite film includes a heat dissipation layer, a buffer layer, and an adhesive layer stacked together. The adhesive layer is fixed to the back of the display panel. The heat dissipation layer has a perforated area, and the orthogonal projection of the perforated area on the flexible circuit board covers the metal connection line of the antenna coil.

13. The display device as claimed in claim 12, wherein, Also includes: Insulating adhesive is filled into the perforated area of ​​the heat dissipation layer.

14. The display device as claimed in claim 11, wherein, The antenna coil is connected to the near-field communication module via a spring.

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