Flexible display module and wearable device

Abstract

The present application relates to the technical field of display devices. Disclosed are a flexible display module and a wearable device. The flexible display module comprises: a flexible display panel; a circuit layer, which is located on a non-light-emitting side of the flexible display panel, and is used for sending a near-field communication signal; a ferrite layer, which is located on the side of the circuit layer that faces away from the flexible display panel; a metal layer, which is located on the side of the ferrite layer that faces away from the circuit layer; and a drive circuit component, wherein a first end of the drive circuit component is connected to the flexible display panel, and a second end of the drive circuit component is folded to the side of the metal layer that faces away from the ferrite layer. The flexible display module can not only ensure NFC-enabled communication, but also perform good heat dissipation, and can also avoid the problem of an insufficient internal space of a device, such that the user experience can be improved.

Description

Flexible display module and wearable device

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410871841.3, filed on July 1, 2024, and entitled "Flexible display module and wearable device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of display devices, in particular to a flexible display module and a wearable device. BACKGROUND

[0004] The main functions of ordinary wearable devices include NFC (near field communication technology), eSIM (embedded SIM card), blood oxygen detection, heart rate detection, etc. The application of flexible products has gradually expanded to the wearable field. For bendable wearable products, it is necessary to ensure the integrity of the functions while meeting the bending requirements. The area of wearable products is relatively small compared to mobile phones, etc. It is necessary to realize bending and functional requirements on a small area, and the support structure of the flexible display module needs to be designed in combination with the special requirements of both. SUMMARY

[0005] The present application provides a flexible display module and a wearable device, which can ensure NFC function communication, good heat dissipation, and avoid the problem of insufficient internal space of the device, and can improve the user experience.

[0006] To achieve the above purpose, the present application provides the following technical solutions:

[0007] A flexible display module comprises:

[0008] A flexible display panel;

[0009] A circuit layer located on the non-light-emitting side of the flexible display panel, the circuit layer being used for emitting near field communication signals;

[0010] A ferrite layer located on the side of the circuit layer away from the flexible display panel;

[0011] A metal layer located on the side of the ferrite layer away from the circuit layer;

[0012] A driving circuit assembly, a first end of the driving circuit assembly being connected with the flexible display panel, and a second end of the driving circuit assembly being folded to the side of the metal layer away from the ferrite layer.

[0013] Optionally, the display panel further comprises a step filling layer;

[0014] The step filling layer is located between the circuit layer and the metal layer, and is used for filling a step generated by a trace in the circuit layer along a first direction, the first direction being an arrangement direction of the flexible display panel and the circuit layer.

[0015] Optionally, the circuit layer comprises a substrate, a signal transmitting trace, and a cover layer;

[0016] The signal transmitting trace is located on one side of the substrate, and is used for transmitting a near field communication signal.

[0017] The cover layer is located on a side of the signal transmitting trace away from the substrate, a projection of the cover layer on the substrate covers a projection of the signal transmitting trace on the substrate, and the cover layer is made of an insulating material.

[0018] Optionally, in the circuit layer, the cover layer is arranged adjacent to the flexible display panel, and the substrate is located on a side of the cover layer away from the flexible display panel.

[0019] Optionally, the circuit layer further comprises a reinforcing layer, and the reinforcing layer is located on a side of the substrate away from the signal transmitting trace.

[0020] In the circuit layer, the reinforcing layer is arranged adjacent to the flexible display panel, and the cover layer is located on a side of the reinforcing layer away from the flexible display panel.

[0021] Optionally, the signal transmitting trace comprises a plurality of turns of coils wound along an edge of the substrate, and each two adjacent turns of the coils have a preset gap.

[0022] The circuit layer further comprises two first feed points located on a side of the substrate away from the flexible display panel, and the first feed points are located at a preset distance from the edge of the substrate.

[0023] Of the two first feed points, one first feed point is connected to a starting end of the signal transmitting trace, and the other first feed point is connected to a terminal end of the signal transmitting trace.

[0024] Optionally, the edge of the circuit layer has at least one trace retraction area, and the signal transmitting trace is routed inward along an edge of the trace retraction area at the trace retraction area.

[0025] Optionally, the driving circuit assembly comprises a chip on film (COF).

[0026] The first end of the CTF is connected with the flexible display panel, and the second end of the CTF is folded to the side of the metal layer away from the ferrite layer, and the side of the CTF facing the metal layer is bonded to the metal layer through a first bonding part;

[0027] The normal projection of the signal transmitting trace on the substrate does not overlap with the normal projection of the first bonding part on the substrate.

[0028] Optionally, the driving circuit assembly further comprises a flexible circuit board;

[0029] The flexible circuit board is located on the side of the metal layer away from the ferrite layer, the flexible circuit board is buckled with the second end of the CTF, and the flexible circuit board has two second feeding points corresponding to the two first feeding points;

[0030] The area opposite to the first feeding point of the ferrite layer, the metal layer and the step-filling layer has a connecting through hole, and the connecting through hole has a first conductive part therein, and the first conductive part does not contact the ferrite layer, the metal layer and the step-filling layer;

[0031] The first feeding point is connected with the corresponding second feeding point through the first conductive part.

[0032] Optionally, the two second feeding points are located on the side of the flexible circuit board facing the metal layer, and the second feeding points are arranged opposite to the first feeding points.

[0033] Optionally, the two second feeding points are located on the side of the flexible circuit board away from the metal layer.

[0034] The normal projection of the connecting through hole on the metal layer does not overlap with the normal projection of the flexible circuit board on the metal layer.

[0035] The flexible display module further comprises two connecting strips corresponding to the two connecting through holes, the connecting strips are located on the side of the flexible circuit board away from the metal layer, and the first conductive part in the connecting through hole is connected with the corresponding second feeding point through the connecting strip.

[0036] Optionally, the side of the flexible circuit board and the metal layer facing the connecting strip has an insulating layer, and the normal projection of the insulating layer on the metal layer covers the normal projection of the middle part of the connecting strip on the metal layer.

[0037] Optionally, the connecting strip is connected with the second feeding point through a second conductive part.

[0038] The second conductive part includes conductive foam, a first side of the conductive foam is connected with the second feed point, a second side of the conductive foam is connected with the connecting strip, and the first side of the conductive foam is away from the second side.

[0039] The flexible display module further includes a sealing adhesive layer, and the sealing adhesive layer is arranged on a side of the connecting strip away from the conductive foam.

[0040] Optionally, the second feed point includes a middle region and a peripheral region arranged around the middle region.

[0041] The second conductive part further includes a fourth pressure-sensitive adhesive layer, the first side of the conductive foam is bonded to the middle region of the second feed point through the fourth pressure-sensitive adhesive layer, and the first side of the conductive foam is in contact with the peripheral region of the second feed point.

[0042] The application further provides a wearable device including any one of the flexible display modules provided in the technical solutions.

[0043] The flexible display module provided by the application includes a flexible display panel, a circuit layer, a ferrite layer, a metal layer and a driving circuit assembly. The circuit layer can be located on the non-light-emitting side of the flexible display panel, and can be used to emit a near field communication signal to communicate with a signal receiver located on the light-emitting side of the flexible display panel. There is no metal material layer between the circuit layer and the signal receiver, so that the signal emitted by the circuit layer towards the signal receiver can be avoided. The ferrite layer and the metal layer can be used as a support structure of the flexible display panel. In addition, the ferrite layer can absorb the electromagnetic wave signal transmitted by the circuit layer, the metal layer can be used as an electromagnetic shielding layer, the electromagnetic wave signal emitted by the circuit layer towards the metal layer can be reflected back by the metal layer after passing through the ferrite layer, and the ferrite layer can perform secondary absorption to avoid the interference of the reflected electromagnetic wave on the communication signal between the circuit layer and the signal receiver. The ferrite layer can avoid the problem of insufficient internal space caused by the large distance between the circuit layer and the metal layer. In addition, the ferrite layer can dissipate heat energy after absorbing electromagnetic waves, and the metal layer can be connected with the middle frame of the wearable device to transmit the heat generated by the film layers and the driving circuit assembly to the middle frame, thereby dissipating heat. The flexible display module can not only ensure NFC function communication, but also dissipate heat well, and can avoid the problem of insufficient internal space, thereby improving user experience. BRIEF DESCRIPTION OF DRAWINGS

[0044] FIG. 1 is a schematic view of a structure of a wearable device;

[0045] FIG. 2 is a schematic view of a structure of an NFC module;

[0046] FIG. 3 is a sectional view of the NFC module in FIG. 2;

[0047] FIG. 4 is a structural schematic diagram of an NFC module;

[0048] FIG. 5 is a sectional view of the NFC module in FIG. 4;

[0049] FIG. 6 is a structural schematic diagram of a wearable device in the related art;

[0050] FIG. 7 is a structural schematic diagram of a flexible display module provided in an embodiment of the present application;

[0051] FIG. 8 is a structural schematic diagram of another flexible display module provided in an embodiment of the present application;

[0052] FIG. 9 is a structural schematic diagram of another flexible display module provided in an embodiment of the present application;

[0053] FIG. 10 is an exploded view of a circuit layer provided in an embodiment of the present application;

[0054] FIG. 11 is a structural schematic diagram of a circuit layer provided in an embodiment of the present application;

[0055] FIG. 12 is an exploded view of another circuit layer provided in an embodiment of the present application;

[0056] FIG. 13 is a wiring schematic diagram of a signal transmission trace provided in an embodiment of the present application;

[0057] FIG. 14 is an enlarged view of a partial region in FIG. 13;

[0058] FIG. 15 is a wiring structural schematic diagram of another signal transmission trace provided in an embodiment of the present application;

[0059] FIG. 16 is a wiring structural schematic diagram of another signal transmission trace provided in an embodiment of the present application;

[0060] FIG. 17 is a structural schematic diagram of a flexible display module provided in an embodiment of the present application;

[0061] FIG. 18 is a connection structural schematic diagram of a flexible circuit board provided in an embodiment of the present application;

[0062] FIG. 19 is a structural schematic diagram of another flexible display module provided in an embodiment of the present application;

[0063] FIG. 20 is a connection structural schematic diagram of another flexible circuit board provided in an embodiment of the present application;

[0064] FIG. 21 is a connection structural schematic diagram of another flexible circuit board provided in an embodiment of the present application.

[0065] Icon: 100-wearable device; 201-NFC circuit layer; 202-separation material; 203-distance calibration plate; 204-signal receiver; 301-separation material; 302-NFC circuit layer; 303-distance calibration plate; 304-signal receiver; 01-cover plate assembly; 02-flexible display panel; 03-support structure; 04-cof; 05-flexible circuit board; 06-NFC circuit; 1-flexible display panel; 2-NFC circuit layer; 21-substrate; 211-via hole; 22-signal transmission trace; 23-cover layer; 24-reinforcement layer; 25-first feed point; 26-connection trace; 3-ferrite layer; 4-metal layer; 5-driving circuit assembly; 51-cof; 511-driving IC; 52-flexible circuit board; 521-second feed point; 522-connection strip; 523-insulating layer; 524-sealing adhesive layer; 6-cover plate assembly; 61-anti-reflective film; 62-first optical adhesive layer; 63-ultra-thin glass; 64-second optical adhesive layer; 65-PET protective film; 71-first pressure-sensitive adhesive layer; 72-second pressure-sensitive adhesive layer; 73-double-sided adhesive tape; 74-fourth pressure-sensitive adhesive layer; 8-first conductive part; 9-second conductive part; 81, 91-soldering layer; 82, 92-SMT reflow soldering layer; 83-conductive adhesive layer; 93-conductive foam. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0067] As shown in FIG. 1, it is a wearable device that can be folded outward. In the related art, for the wearable device 100 that is folded outward, in order to ensure the identification distance between the NFC circuit in the device and the external signal receiver, the NFC circuit in the wearable device needs to be arranged between the flexible display panel and the main control circuit board.

[0068] The inventors of the present application have tested the state of the NFC circuit when in use. In one embodiment, an NFC module can include an NFC circuit layer, a spacer material. One side of the NFC module can be provided with a distance calibration plate and a signal receiver for testing. The NFC circuit layer is used to transmit near field communication signals, the signal receiver is used to identify the signals emitted by the NFC circuit layer, and the distance calibration plate is used to calibrate the identification distance between the NFC circuit layer and the signal receiver. By replacing the spacer material, the effect of different materials on the identification distance between the NFC circuit layer and the signal receiver can be tested. In FIGS. 2 and 3, the spacer material 202 is placed between the NFC circuit layer 201 and the signal receiver 204, and the spacer material 202 and the signal receiver 204 have a distance calibration plate 203 therebetween. The specific test results are shown in Table 1. In FIGS. 4 and 5, the spacer material 301 is placed on the side of the NFC circuit layer 302 away from the signal receiver 304, and the NFC circuit layer 302 and the signal receiver 304 have a distance calibration plate 303 therebetween. The specific test results are shown in Table 2.

[0069] Table 1

[0070] Table 2

[0071] As can be seen from the test results in Table 1, when no spacer material is provided between the NFC circuit layer and the signal receiver, the NFC circuit layer and the signal receiver can normally communicate, and the identification distance is 75 mm. When the spacer material between the NFC circuit layer and the signal receiver is a patterned stainless steel (SUS) sheet, or a non-patterned stainless steel sheet, or a carbon fiber, it will have some effect on the identification distance between the NFC circuit layer and the signal receiver. If a full layer of metal is provided between the NFC circuit layer and the signal receiver, the electromagnetic wave signals emitted by the NFC circuit layer will be completely reflected back by the metal layer, and the signal receiver will not be able to identify the signals.

[0072] As can be seen from the test results in Table 2, when the spacer material above the NFC circuit layer is a stainless steel material with a thickness of 30 μm, and the distance L between the spacer material and the NFC circuit layer is 0, the electromagnetic waves reflected back by the spacer material will interfere with the NFC electromagnetic waves, and the NFC cannot be used normally, with an identification distance of 0. When the stainless steel spacer material is kept at a certain distance from the NFC circuit layer (L≥2 mm in FIG. 5), the interference effect of the reflected waves is reduced. However, due to the limited internal space of smart wearable devices, it is not possible to set the distance between the NFC circuit layer and the metal layer.

[0073] Based on the test results, as shown in FIG. 6, in an embodiment, the wearable device can be configured to include a cover plate assembly 01, a flexible display panel 02, a support structure 03, a chip on film (COF) 04, a flexible printed circuit (FPC) 05, an NFC circuit 06, a main control circuit board, the support structure 03 is used to support the flexible display panel 02, the first end of the chip on film 04 is connected with the flexible printed circuit 05, and the second end is folded to the side of the support structure away from the flexible display panel 02, the flexible printed circuit 05 is located on the side of the support structure 03 away from the flexible display panel 02 and connected with the second end of the chip on film 04, the NFC circuit 06 is integrated on the side of the flexible printed circuit 05 away from the support structure, and the main control circuit board is located on the side of the support structure away from the flexible display panel and connected with the flexible printed circuit.

[0074] Considering the signal shielding and other problems, the support structure cannot be a metal material, and at the same time needs to play a supporting role, so the material of the support structure can be polyethylene terephthalate (PET), polyimide and other organic materials, and the thickness can be between 0.1 mm and 0.2 mm to ensure the bending characteristics. However, the thermal conductivity index of organic materials such as PET is 0.24 W / (m·K), which is much smaller than the thermal conductivity index of aluminum alloy 50-100 W / (m·K), and the heat of the driving IC on the chip on film cannot be dispersed and spread to the main frame of the whole machine through the support structure, resulting in heat accumulation and poor heat dissipation of the device.

[0075] To solve the above technical problems, an embodiment of the present application provides a flexible display module, as shown in FIG. 7, comprising:

[0076] a flexible display panel 1, the flexible display panel 1 can include a light-out side and a non-light-out side facing away from each other;

[0077] a circuit layer 2, the circuit layer 2 is located on the non-light-out side of the flexible display panel 1, and the circuit layer 2 is used to emit near field communication signals;

[0078] a ferrite layer 3, the ferrite layer 3 is located on the side of the circuit layer 2 away from the flexible display panel 1;

[0079] a metal layer 4, the metal layer 4 is located on the side of the ferrite layer 3 away from the circuit layer 2;

[0080] a driving circuit assembly 5, the first end of the driving circuit assembly 5 is connected with the flexible display panel 1, and the second end of the driving circuit assembly 5 is folded to the side of the metal layer 4 away from the ferrite layer 3.

[0081] The flexible display module provided by the embodiment of the application comprises a flexible display panel 1, a circuit layer 2, a ferrite layer 3, a metal layer 4 and a driving circuit assembly 5. The circuit layer 2 can be located on the non-light-emitting side of the flexible display panel 1, and can be used to emit a near field communication signal to communicate with a signal receiver located on the light-emitting side of the flexible display panel 1. The circuit layer 2 and the signal receiver do not have a whole metal material layer, so that the signal emitted by the circuit layer 2 towards the signal receiver can be avoided. The ferrite layer 3 and the metal layer 4 can be used as a support structure of the flexible display panel 1. In addition, the ferrite layer 3 can absorb the electromagnetic wave signal transmitted by the circuit layer 2, the metal layer 4 can be used as an electromagnetic shielding layer, the electromagnetic wave signal emitted by the circuit layer 2 towards the metal layer 4 can be reflected back by the metal layer 4 after passing through the ferrite layer, the ferrite layer 3 can perform secondary absorption to avoid the reflected electromagnetic wave from interfering with the communication signal between the circuit layer 2 and the signal receiver. The ferrite layer 3 can avoid the problem of insufficient internal space caused by the large distance between the circuit layer 2 and the metal layer 4. In addition, after the ferrite layer absorbs the electromagnetic wave, the heat is dissipated, the metal layer 4 can be connected with the middle frame of the wearable device, and the heat of each film layer and the heat dissipated by the driving circuit assembly 5 can be transmitted to the middle frame to dissipate heat. The above flexible display module can not only ensure the NFC function communication, but also can dissipate heat well, and can avoid the problem of insufficient internal space of the device, and can improve the user experience.

[0082] Specifically, the circuit layer 2 can be a coil antenna similar to RFID with a frequency of 13.56 MHz, and energy transmission is achieved through magnetic field coupling.

[0083] The material of the ferrite layer 3 can be nanocrystalline material, which belongs to inorganic material, and can also be other materials, which is not limited here and is determined according to the actual situation.

[0084] The material of the metal layer 4 can be copper foil, and can also be other metal materials, which is not limited here and is determined according to the actual situation. In order to ensure the bending effect of the flexible display module, the thickness of the ferrite layer 3 and the metal layer 4 can be determined according to the actual situation, which is not limited here.

[0085] In the embodiments of the present application, the flexible display module can further include a cover assembly 6, which can include an anti-reflective film 61, an ultra-thin glass 63, and a PET protective film 65. The PET protective film 65 is located on the light-emitting side of the flexible display panel 1. The ultra-thin glass 63 is located on the side of the PET protective film 65 away from the flexible display panel 1. The anti-reflective film 61 is located on the side of the ultra-thin glass 63 away from the PET protective film 65. The anti-reflective film 61 and the ultra-thin glass 63 can be bonded by a first optical adhesive layer 62. The ultra-thin glass 63 and the PET protective film 65 can be bonded by a second optical adhesive layer 64. The anti-reflective film 61 can reduce reflectivity and reduce the reflection of external light. The ultra-thin glass 63 can reduce the tensile strain of the anti-reflective film 61, so that the anti-reflective film 61 is uniformly stressed. The three-layer structure of the anti-reflective film 61, the ultra-thin glass 63, and the PET protective film 65 can improve the impact resistance of the device.

[0086] In the embodiments of the present application, the flexible display module can further include a step filling layer. The step filling layer is located between the circuit layer 2 and the metal layer 4. The step filling layer is used to fill the step generated by the traces in the circuit layer 2 along the first direction. The first direction is the arrangement direction of the flexible display panel 1 and the circuit layer 2.

[0087] Because the circuit layer 2 in the flexible display module is arranged close to the flexible display panel 1, the traces in the circuit layer 2 can cause the flexible display module to generate a step along the arrangement direction of the flexible display panel 1 and the circuit layer 2. This can cause the traces in the circuit layer 2 to leave marks on the light-emitting side of the flexible display panel 1, which can cause the flexible display module to have a slight risk of mold printing. The step filling layer in the flexible display module can fill and cover the step generated by the traces in the circuit layer 2 on the side of the circuit layer 2 away from the flexible display panel 1. This can make the surface of the circuit layer 2 in contact with the flexible display panel 1 more flat, which can help to reduce mold printing.

[0088] In the embodiments of the present application, as shown in FIGS. 8 and 9, the step filling layer can include a first pressure-sensitive adhesive layer 71 and a second pressure-sensitive adhesive layer 72. The first pressure-sensitive adhesive layer 71 is attached between the circuit layer 2 and the ferrite layer 3. The second pressure-sensitive adhesive layer 72 is attached between the ferrite layer 3 and the metal layer 4.

[0089] Because the pressure-sensitive adhesive has good fluidity, it can well fill the step generated by the traces. The circuit layer 2 and the ferrite layer 3 are bonded by the first pressure-sensitive adhesive layer 71. The ferrite layer 3 and the metal layer 4 are bonded by the second pressure-sensitive adhesive layer 72. This can achieve fixed connection between the circuit layer 2, the ferrite layer 3, and the metal layer 4. The first pressure-sensitive adhesive layer 71 and the second pressure-sensitive adhesive layer 72 can fill and cover the step generated by the traces in the circuit layer 2, which can help to reduce mold printing on the light-emitting side of the flexible display module.

[0090] Specifically, the first pressure-sensitive adhesive layer 71 and the second pressure-sensitive adhesive layer 72 are double-sided adhesive tape 73. The thicknesses of the first pressure-sensitive adhesive layer 71 and the second pressure-sensitive adhesive layer 72 need to meet the requirement of filling the step difference caused by the traces in the circuit layer 2, which is not limited here and can be determined according to actual conditions. For example, the sum of the thickness of the first pressure-sensitive adhesive layer 71 and the thickness of the second pressure-sensitive adhesive layer 72 can be greater than or equal to 50 μm.

[0091] In addition, since the material of the ferrite layer 3 is an inorganic material, the surface of the inorganic material is uneven and has poor flatness. If the ferrite layer 3 directly contacts the circuit layer 2, the orange peel phenomenon can be observed on the light-emitting side of the flexible display panel 1, affecting the user experience. The better flowability of the first pressure-sensitive adhesive layer 71 and the second pressure-sensitive adhesive layer 72 can fill the uneven surfaces on both sides of the ferrite layer 3, ensure the flatness of the surface of the flexible display panel 1 in contact with the circuit layer 2, and avoid the orange peel phenomenon.

[0092] In the embodiment of the present application, the ferrite layer 3, the first pressure-sensitive adhesive layer 71 and the second pressure-sensitive adhesive layer 72 can be shipped as a whole, and then assembled with the circuit layer 2 and the metal layer 4, facilitating the assembly of the flexible display module.

[0093] In the embodiment of the present application, as shown in FIGS. 10 and 11, the circuit layer 2 can include a substrate 21, a signal transmission trace 22 and a cover layer 23. The signal transmission trace 22 is located on one side of the substrate 21 and is used to emit near field communication signals. The cover layer 23 can be located on the side of the signal transmission trace 22 away from the substrate 21, and the orthographic projection of the cover layer 23 on the substrate 21 covers the orthographic projection of the signal transmission trace 22 on the substrate 21. The material of the cover layer 23 is an insulating material.

[0094] In the above-mentioned circuit layer 2, the cover layer 23 can protect the signal transmission trace 22. When the circuit layer 2 is manufactured, the signal transmission trace 22 can be first arranged on the substrate 21, and then the cover layer 23 can be formed on the side of the signal transmission trace 22 away from the substrate 21, so that the circuit layer 2 is formed as a whole. The circuit layer 2 can be uniformly manufactured and then transported to an assembly location for assembly with other components. The cover layer 23 can protect the signal transmission trace 22 during the transportation of the circuit layer 2, avoiding damage to the signal transmission trace 22.

[0095] Specifically, the material of the substrate 21 can be an insulating material, for example, a PET material, or other materials, which are not limited here and can be determined according to actual conditions. The material of the signal transmission trace 22 can be copper or other metal materials, which are not limited here and can be determined according to actual conditions.

[0096] Specifically, in the above-mentioned circuit layer 2, the cover layer 23 can be arranged adjacent to the flexible display panel 1, and the substrate 21 is located on the side of the cover layer away from the flexible display panel 1, as shown in FIG. 8. The cover layer 23 can avoid short circuit between the signal transmission trace 22 in the circuit layer 2 and the flexible display panel 1, and improve the use safety of the NFC function.

[0097] Optionally, as shown in FIG. 12, the circuit layer 2 can further include a reinforcing layer 24, which can be located on the side of the substrate 21 away from the signal transmission trace 22; in the circuit layer 2, the reinforcing layer 24 can be arranged adjacent to the flexible display panel 1, and the cover layer is located on the side of the reinforcing layer 24 away from the flexible display panel 1, as shown in FIG. 9. The reinforcing layer 24 and the substrate 21 are located between the signal transmission trace 22 and the flexible display panel 1, which can increase the mechanical strength of the side of the signal transmission trace 22 adjacent to the flexible display panel 1, and can optimize the reduction of the trace mold of the flexible display module.

[0098] Specifically, the reinforcing layer 24 can be a black insulating material, which can insulate the circuit layer 2 from the flexible display panel 1, and can avoid light shielding treatment of the circuit layer 2, thereby improving the light reflection phenomenon on the surface of the circuit layer 2. The material of the reinforcing layer 24 can be polyimide, polyethylene terephthalate, an ink layer, etc., and can also be other materials, which are not limited here.

[0099] In order to ensure the mechanical strength of the reinforcing layer 24 and the substrate 21, the sum of the thickness of the reinforcing layer 24 and the thickness of the substrate 21 can be greater than or equal to 88 μm. Specifically, the thickness of the reinforcing layer 24 and the substrate 21 is not limited here and is determined according to the actual situation.

[0100] In the embodiments of the present application, as shown in FIGS. 10 to 14, the above-mentioned signal transmission trace 22 can include a plurality of turns of coils wound along the edge of the substrate 21, and the adjacent coils have a preset gap; the circuit layer 2 further includes two first feed points 25 located on the side of the substrate 21 away from the flexible display panel 1, and the first feed points 25 have a preset distance from the edge of the substrate 21; among the two first feed points 25, one first feed point 25 is connected to the starting point a of the signal transmission trace 22, and the other first feed point 25 is connected to the terminal end b of the signal transmission trace 22.

[0101] As shown in FIGS. 10 and 11, a schematic diagram of the structure of the circuit layer 2 in FIG. 8 is shown. In the circuit layer 2, the cover layer 23 is arranged adjacent to the flexible display panel 1, the signal transmission trace 22 is arranged between the cover layer 23 and the substrate 21, the first feeding point 25 and the second feeding point 521 are arranged on the side of the substrate 21 away from the flexible display panel 1, one first feeding point 25 can be connected to the starting end a of the signal transmission trace 22 through a through hole in the substrate 21, and the other first feeding point 25 can be connected to the terminal end b of the signal transmission trace 22 through a through hole in the substrate 21. If the distance between the two first feeding points 25 is large, the circuit layer 2 can further include a connecting trace 26, the connecting trace 26 is arranged on the side of the substrate 21 away from the flexible display panel 1, one first feeding point 25 can be connected to the first end of the connecting trace 26, and the connecting trace 26 can be connected to the starting end or the terminal end of the signal transmission trace 22 through a through hole in the substrate 21.

[0102] As shown in FIG. 12, a schematic diagram of the structure of the circuit layer 2 in FIG. 9 is shown. In the circuit layer 2, the reinforcing layer 24 and the substrate 21 are arranged adjacent to the flexible display panel 1, the signal transmission trace 22 and the two first feeding points 25 can be arranged on the side of the substrate 21 away from the flexible display panel 1, one first feeding point 25 can be directly connected to the starting end a of the signal transmission trace 22, and the other first feeding point 25 can be directly connected to the terminal end b of the signal transmission trace 22.

[0103] Specifically, as shown in FIGS. 13 and 14, the signal transmission trace 22 can be a multi-turn coil wound along the edge of the substrate 21, and the two adjacent turns of the coil have a preset gap, i.e., the signal transmission trace 22 is arranged along the edge of the flexible display module. In order to ensure the arrangement position of the first feeding point 25, the starting end and the terminal end of the signal transmission trace 22 are arranged inwardly toward the center of the substrate 21, and the two first feeding points 25 can have a preset distance D1 from the edge of the substrate 21. The smaller the preset distance of the first feeding point 25 from the edge of the substrate 21, i.e., the closer the first feeding point 25 is to the edge of the substrate 21, the lighter the mold mark of the flexible display module generated by the edge trace of the first feeding point 25.

[0104] Specifically, the preset distance of the first feeding point 25 from the edge of the substrate 21 can be 5 mm to 10 mm, which can ensure the adhesion strength between the film layers, and can also be other ranges, which are not limited here and are determined according to the actual situation.

[0105] Specifically, the number of turns of the above-mentioned signal transmission trace 22 can be 2 turns, which can be a single-layer design, and can also be multiple turns, which are not limited here and are determined according to the actual situation. In the signal transmission trace 22, the trace spacing D2 between the two adjacent turns of the coil can be 0.2 mm, the trace width D3 can be 0.4 mm to 0.8 mm, and the trace thickness can be less than or equal to 12 μm.

[0106] In consideration of the flexible display module and the overall environment, the NFC signal is simulated in the present application, the number of turns of the signal reflection wire coil is 2 turns, the wire spacing is 0.2 mm, the wire width is 0.4 mm and 1 mm respectively, and the wire thickness is less than or equal to 12 μm. According to the test results, when the wire width of the signal transmission wire 22 is 1.0 mm, the signal field strength is relatively uniform, but the inductance is low, the overall NFC signal is low, and when the wire width of the signal transmission wire 22 is 0.4 mm, the inductance is appropriate, but the signal field strength center is obviously hollow, and the NFC signal at the middle position is weak. In consideration of the inductance and field strength simulation test, the wire width of the signal transmission wire 22 can be designed as 0.4 mm-0.8 mm.

[0107] In the embodiment of the present application, in order to solve the problem of weak NFC signal at the center of the device, as shown in FIG. 15, the edge of the circuit layer 2 can have at least one wire inwardly recessed area C, and the signal transmission wire 22 is arranged inwardly recessed along the edge of the wire inwardly recessed area C. By arranging the signal transmission wire 22 inwardly recessed, the distance between the signal transmission wire 22 at the wire inwardly recessed area C and the center of the device can be reduced, so that the center of the device is within the radiation range of the electromagnetic wave signal emitted by the signal transmission wire 22, thereby enhancing the NFC signal strength at the center of the device.

[0108] In the embodiment of the present application, as shown in FIGS. 16 and 17, the driving circuit assembly 5 can include a chip on film 51; wherein the first end of the chip on film 51 is connected with the flexible display panel 1, the second end of the chip on film 51 is folded to the side of the metal layer 4 away from the ferrite layer 3, and the side of the chip on film 51 facing the metal layer 4 is adhered to the metal layer 4 through a first adhesive (not shown in FIG. 17); the orthographic projection of the signal transmission wire 22 on the substrate 21 does not overlap with the orthographic projection of the first adhesive on the substrate 21, so that the signal transmission wire 22 and the first adhesive are positionally avoided. As shown in FIG. 16, the area D in FIG. 16 is the area corresponding to the first adhesive, and the signal transmission wire avoids the first adhesive.

[0109] Specifically, the chip on film 51 is provided with a driving IC 511, which can be arranged on the side of the second end of the chip on film 51 away from the metal layer 4. The driving IC 511 can provide display driving signals for the flexible display panel 1, and the chip on film 51 is adhered to the metal layer 4 through the first adhesive, so that the metal layer 4 can be connected with the middle frame to dissipate heat for the driving IC 511.

[0110] In addition, the first adhesive part can be a third pressure-sensitive adhesive layer. Since the traces in the circuit layer 2 form a step, different specifications of the pressure-sensitive adhesive have different step filling rates, which can cause the thickness of the corresponding position to be unable to be accurately controlled. The step filling rates of the third pressure-sensitive adhesive layer, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive layer are different. In order to avoid the thickness of the corresponding position of the third pressure-sensitive adhesive layer being unable to be accurately controlled, the signal transmission trace 22 in the circuit layer 2 can be avoided in the area D corresponding to the third pressure-sensitive adhesive layer, as shown in FIG. 16, to avoid this problem and ensure the accuracy of the thickness of the flexible display module at the position of the chip on film 51.

[0111] In the embodiments of the present application, as shown in FIGS. 17 and 18, the driving circuit assembly 5 can further include a flexible circuit board 52. The flexible circuit board 52 is located on the side of the metal layer 4 away from the ferrite layer 3. The flexible circuit board 52 is buckled with the second end of the chip on film 51. The flexible circuit board 52 has two second feed points 521 corresponding to the two first feed points 25. The area of the ferrite layer 3, the metal layer 4, and the step filling layer opposite to the first feed point 25 can have a connection through hole O. The connection through hole O has a first conductive part 8 therein. The first conductive part 8 does not contact the ferrite layer 3, the metal layer 4, and the step filling layer. The first feed point 25 is connected with the corresponding second feed point 521 through the first conductive part 8.

[0112] In the driving circuit assembly 5, the first end of the flexible circuit board 52 can be buckled with the second end of the chip on film 51. The second end of the flexible circuit board 52 can be buckled with a master control circuit board. The master control circuit board transmits signals to the driving IC 511 and the circuit layer 2 through the flexible circuit board 52 to control the display state of the flexible display panel 1 and the opening and closing of the NFC function. The flexible circuit board 52 can be adhered to the metal layer 4 through double-sided adhesive 73. The signal transmission trace 22 in the circuit layer 2 can be avoided when wiring, to avoid the thickness of the flexible display module in the area where the flexible circuit board 52 is located being inaccurate.

[0113] When the NFC circuit layer 2 trace is integrated on the flexible circuit board 52, the trace in the circuit layer 2 is directly connected with the flexible circuit board 52, and does not need a feed point. When the NFC circuit layer 2 is located between the ferrite layer 3 and the flexible display panel 1, the signal transmission trace 22 in the circuit layer 2 needs to be led out a feed point and connected with the feed point on the flexible circuit board 52.

[0114] The two second feeding points 521 on the flexible circuit board 52 are connected to the two first feeding points 25 on the circuit layer 2 through the first conductive part 8 in the connecting via hole. The first conductive part 8 can fill the thickness gap at the connecting via hole O, so as to avoid the occurrence of mold printing at the connecting via hole O. The first conductive part 8 does not contact the ferrite layer 3, the metal layer 4 and the gap filling layer, so as to avoid the influence of the ferrite layer 3 and the metal layer 4 on the signal transmitted by the first conductive part 8, and ensure the realization of the NFC function.

[0115] Specifically, as shown in FIGS. 8 and 9, the area opposite to the first feeding point 25 of the first pressure-sensitive adhesive layer 71, the ferrite layer 3, the second pressure-sensitive adhesive layer 72 and the metal layer 4 forms a via hole, the via holes on the film layers are connected to form a connecting via hole O, and the first conductive part 8 is formed in the connecting via hole O.

[0116] Specifically, as shown in FIG. 18, the first conductive part 8 can be formed by a solder layer 81, an SMT reflow soldering layer 82 and a conductive adhesive layer 83, that is, the first feeding point 25 and the second feeding point 521 can be connected through the surface mount technology.

[0117] In the embodiment of the present application, as shown in FIGS. 17 and 18, the two second feeding points 521 can be located on the side of the flexible circuit board 52 facing the metal layer 4, and the second feeding point 521 is arranged opposite to the first feeding point 25, which is simple in structure and easy to realize.

[0118] Alternatively, as shown in FIG. 19, the two second feeding points 521 can also be located on the side of the flexible circuit board 52 away from the metal layer 4; the orthographic projection of the connecting via hole O on the metal layer 4 does not overlap with the orthographic projection of the flexible circuit board 52 on the metal layer 4, that is, the positions of the first feeding point 25 and the second feeding point 521 are relatively staggered; the flexible display module can further include two connecting strips 522 corresponding to the two connecting via holes O, the connecting strips 522 are located on the side of the flexible circuit board 52 away from the metal layer 4, the first conductive part in the connecting via hole is connected to the corresponding second feeding point 521 through the connecting strip 522, and the flexible circuit board 52 and the circuit layer 2 can be connected to transmit signals through the connecting strip 522.

[0119] Specifically, the material of the connecting strip 522 can be a metal conductive material or other conductive material, which is not limited here and is determined according to the actual situation.

[0120] Specifically, as shown in FIG. 19, the side of the flexible circuit board 52 and the metal layer 4 facing the connecting strip 522 can have an insulating layer 523, and the orthographic projection of the insulating layer 523 on the metal layer 4 covers the orthographic projection of the middle part of the connecting strip 522 on the metal layer 4.

[0121] The first end of the connecting strip 522 can be connected with the first conductive part 8, the second end of the connecting strip 522 can be connected with the second feed point 521, and the portion between the first end of the connecting strip 522 and the second end of the connecting strip 522 is an intermediate portion. The intermediate portion of the connecting strip 522 can be prevented from contacting the metal layer 4 by the insulating layer 523, so as to avoid affecting the NFC signal transmission.

[0122] In the embodiment of the present application, as shown in FIG. 20, the connecting strip 522 can be connected with the second feed point 521 through the second conductive part 9. The second conductive part 9 can include a conductive foam 93, the first side of the conductive foam 93 is connected with the second feed point 521, the second side of the conductive foam 93 is connected with the connecting strip 522, and the first side of the conductive foam 93 is away from the second side. The flexible display module further includes a sealing adhesive layer 524, which is arranged on the side of the connecting strip 522 away from the conductive foam 93.

[0123] Specifically, the outer side of the conductive foam 93 can be glued and sealed, and the glue can be cured by UV after being applied. The sealing adhesive layer 524 is formed, as shown in FIG. 20, which can wrap the outer side of the second conductive part 9 and the second end of the connecting strip 522, to ensure the connection between the second conductive part 9 and the connecting strip 522 and the flexible circuit board 52. According to the compression rate of the conductive foam 93, curing under a certain pressure is required to ensure the connection effect between the connecting strip 522 and the second feed point 521 of the flexible circuit board 52.

[0124] Specifically, the second conductive part 9 can include a solder layer 91, an SMT reflow solder layer 92 and a conductive foam 93, that is, the second feed point 521 of the flexible circuit board 52 and the connecting strip 522 can be connected by surface mount technology.

[0125] Specifically, as shown in FIG. 21, the second feed point 521 can include an intermediate region and a peripheral region arranged around the intermediate region. The second conductive part 9 further includes a fourth pressure-sensitive adhesive layer 74, the first side of the conductive foam 93 can be bonded to the intermediate region of the second feed point 521 through the fourth pressure-sensitive adhesive layer 74, and the first side of the conductive foam 93 is in contact with the peripheral region of the second feed point 521. The fourth pressure-sensitive adhesive layer 74 can fixedly connect the second feed point 521 of the flexible circuit board 52 and the conductive foam 93, so that the conductive foam 93 is in contact with the peripheral region of the second feed point 521, that is, the conductive foam 93 is semi-wrapped to ensure the normal transmission of signals between the flexible circuit board 52 and the circuit layer 2.

[0126] Specifically, the above-mentioned conductive foam 93 can also be replaced by conductive cloth. The connecting strip 522 and the second feed point 521 on the flexible circuit board 52 can also be connected by signal buckle connection, which is not limited here and is determined according to the actual situation.

[0127] The embodiment of the present application further provides a wearable device comprising the flexible display module provided in any of the technical solutions.

[0128] Obviously, various modifications and variations of the present application can be made by those skilled in the art without departing from the spirit and scope of the application. Thus, it is intended that the present application cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A flexible display module, comprising, include: Flexible display panel; A circuit layer located on the non-light-emitting side of the flexible display panel, the circuit layer being used to emit near-field communication signals; A ferrite layer is located on the side of the circuit layer opposite to the flexible display panel. A metal layer located on the side of the ferrite layer opposite to the circuit layer; A driving circuit assembly, wherein a first end of the driving circuit assembly is connected to the flexible display panel, and a second end of the driving circuit assembly is folded to the side of the metal layer opposite to the ferrite layer. 2.The flexible display module of claim 1, wherein, It also includes a step fill layer; The step filler layer is located between the circuit layer and the metal layer. The step filler layer is used to fill the step difference generated by the traces in the circuit layer along a first direction, where the first direction is the arrangement direction of the flexible display panel and the circuit layer. 3.The flexible display module of claim 2, wherein, The circuit layer includes a substrate, signal transmission traces, and a cover layer; The signal transmission trace is located on one side of the substrate, and the signal transmission trace is used to emit near-field communication signals; The cover layer is located on the side of the signal transmission trace away from the substrate. The orthographic projection of the cover layer on the substrate covers the orthographic projection of the signal transmission trace on the substrate. The material of the cover layer is an insulating material.

4. The flexible display module of claim 3, wherein, In the circuit layer, the cover layer is disposed adjacent to the flexible display panel, and the substrate is located on the side of the cover layer opposite to the flexible display panel. 5.The flexible display module of claim 3, wherein, The circuit layer further includes a reinforcement layer, which is located on the side of the substrate away from the signal transmission trace; In the circuit layer, the reinforcing layer is disposed adjacent to the flexible display panel, and the cover layer is located on the side of the reinforcing layer opposite to the flexible display panel. 6.The flexible display module of any one of claims 3-5, wherein, The signal transmission trace includes a multi-turn coil wound along the edge of the substrate, with a preset gap between two adjacent turns of the coil; The circuit layer also includes two first feed points located on the side of the substrate away from the flexible display panel, and the first feed points are at a predetermined distance from the edge of the substrate; Of the two first feed points, one first feed point is connected to the starting end of the signal transmission route, and the other first feed point is connected to the ending end of the signal transmission route.

7. The flexible display module of claim 6, wherein, The edge of the line layer has at least one trace recess, and the signal transmission trace is routed inward along the edge of the trace recess at the trace recess.

8. The flexible display module of claim 6 or 7, wherein, The drive circuit assembly includes a flip-chip thin film; The first end of the flip-chip film is connected to the flexible display panel, the second end of the flip-chip film is folded to the side of the metal layer away from the ferrite layer, and the side of the flip-chip film facing the metal layer is bonded to the metal layer through the first adhesive portion. The orthographic projection of the signal transmission trace on the substrate does not overlap with the orthographic projection of the first adhesive portion on the substrate. 9.The flexible display module of claim 8, wherein, The drive circuit assembly also includes a flexible circuit board; The flexible circuit board is located on the side of the metal layer away from the ferrite layer. The flexible circuit board is fastened to the second end of the flip-chip film. The flexible circuit board has two second feed points that correspond one-to-one with the two first feed points. The iron-oxygen layer, the metal layer and the step difference filling layer have a connection through hole opposite to the first feeding point, and the connection through hole has a first conductive part therein, and the first conductive part is not in contact with the iron-oxygen layer, the metal layer and the step difference filling layer; The first feeding point is connected with the corresponding second feeding point through the first conductive part.

10. The flexible display module of claim 9, wherein, The two second feeding points are located on the side of the flexible circuit board facing the metal layer, and the second feeding points are arranged opposite to the first feeding point. 11.The flexible display module of claim 9, wherein, The two second feeding points are located on the side of the flexible circuit board away from the metal layer; The orthographic projection of the connection through hole on the metal layer does not overlap with the orthographic projection of the flexible circuit board on the metal layer; The flexible display module further comprises two connection strips corresponding to the two connection through holes one by one, the connection strips are located on the side of the flexible circuit board away from the metal layer, and the first conductive part in the connection through hole is connected with the corresponding second feeding point through the connection strip. 12.The flexible display module of claim 11, wherein, The side of the flexible circuit board and the metal layer facing the connection strip has an insulating layer, and the orthographic projection of the insulating layer on the metal layer covers the orthographic projection of the middle part of the connection strip on the metal layer.

13. The flexible display module of claim 11 or 12, wherein, The connection strip is connected with the second feeding point through a second conductive part; The second conductive part comprises conductive foam, a first side of the conductive foam is connected with the second feeding point, a second side of the conductive foam is connected with the connection strip, and the first side of the conductive foam is away from the second side of the conductive foam; The flexible display module further comprises a sealing adhesive layer, and the sealing adhesive layer is arranged on the side of the connection strip away from the conductive foam.

14. The flexible display module of claim 13, wherein, The second feeding point comprises a middle region and a peripheral region arranged around the middle region; The second conductive part further comprises a fourth pressure-sensitive adhesive layer, the first side of the conductive foam is bonded to the middle region of the second feeding point through the fourth pressure-sensitive adhesive layer, and the first side of the conductive foam is in contact with the peripheral region of the second feeding point.

15. A wearable device, wherein, The flexible display module comprises the flexible display module according to any one of claims 1-14.

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