Flexible flat cable, manufacturing process thereof and electronic equipment

Abstract

The invention provides a flexible flat cable and a manufacturing process thereof, and an electronic device, the flexible flat cable comprises a signal layer and shielding films, the signal layer is used for transmitting signals, the shielding films are attached to the surfaces of the two sides of the signal layer in the thickness direction, the shielding films are used for carrying out insulation protection on the signal layer, and electromagnetic shielding can be realized. The signal layer and the shielding films on the two sides of the signal layer jointly form the flexible flat cable, and the flexible flat cable is simple in structure and low in cost. According to the flexible flat cable, the shielding film is designed, on the basis that the loss performance and impedance of the flexible flat cable are controllable, the thickness of the shielding film is reduced, and the thickness of the shielding film is controlled between 0.5 micrometer and 12 micrometers, so that the overall thickness of the flexible flat cable is reduced, and the application range of the flexible flat cable is expanded.

Description

Technical Field

[0001] The present application relates to the field of electronic equipment, and in particular to a flexible flat cable and a manufacturing process thereof, and electronic equipment. Background Art

[0002] Flexible Flat Cable (FFC) has the advantages of good loss performance and low cost, and is increasingly used in electronic consumer products.

[0003] The good loss performance of the flexible flat cable is due to the shielding films set on both sides of the flexible flat cable, which realize electromagnetic shielding to reduce the loss of the flexible flat cable. However, it is precisely because the shielding films are set on both sides of the flexible flat cable that the thickness of the flexible flat cable is relatively large. The flexible flat cable can only be used in PC (Personal Computer) products with larger space. In mobile phones, tablet computers, PCs and other products with smaller space, only thinner FPC (Flexible Printed Circuit) can be used, which limits the application of flexible flat cables. Summary of the invention

[0004] The present application provides a flexible flat cable and a manufacturing process thereof, and an electronic device. The flexible flat cable has a small thickness, good loss performance, and a wider range of applications.

[0005] A first aspect of the present application provides a flexible flat cable, comprising a signal layer and a shielding film, wherein the shielding film is attached to both side surfaces of the signal layer in a thickness direction, and the thickness of the shielding film ranges from 0.5 μm to 12 μm.

[0006] The flexible flat cable provided by the present application includes a signal layer and a shielding film, wherein the signal layer is used to transmit signals, the shielding film is attached to the two side surfaces of the signal layer in the thickness direction, the shielding film is used to insulate and protect the signal layer, and can realize electromagnetic shielding, the signal layer and the shielding films on both sides thereof together constitute a flexible flat cable, and the structure of the flexible flat cable is simple and the cost is low. Among them, by designing the shielding film, on the basis of ensuring the loss performance and controllable impedance of the flexible flat cable, the thickness of the shielding film is thinned, and the thickness of the shielding film is controlled to be between 0.5μm-12μm, thereby reducing the overall thickness of the flexible flat cable and expanding the application range of the flexible flat cable.

[0007] In a possible implementation, the signal layer includes a conductor layer and a hot-melt adhesive layer, the hot-melt adhesive layer is wrapped around the outer periphery of the conductor layer, and the shielding film is attached to the surface of the hot-melt adhesive layer;

[0008] The conductor layer includes a plurality of conductors, the plurality of conductors include a plurality of signal wires and a plurality of ground wires, the ground wires are arranged at intervals along the plane direction of the conductor layer, and the ground wires are in electrical contact with the shielding film.

[0009] By arranging multiple grounding wires at intervals along the plane direction of the conductor layer, each grounding wire is in electrical contact with the shielding film, which increases the grounding parts of the flexible flat cable, effectively shortens the grounding return path, improves the grounding effect of the flexible flat cable, weakens the resonance of the insertion loss, and improves the signal quality of the flexible flat cable.

[0010] In a possible implementation, the hot melt adhesive layer is provided with a plurality of contact grooves, each contact groove corresponds to each grounding wire one by one, and the contact grooves extend to expose the grounding wires, and the grounding wires are in electrical contact with the shielding film through the contact grooves.

[0011] By opening multiple contact grooves on the hot melt adhesive layer, each contact groove corresponds to each grounding wire and exposes each grounding wire. Thus, each grounding wire can be electrically contacted with the shielding film through the contact groove to ground the shielding film, and the grounding return path is shorter, which can improve the grounding effect of the flexible flat cable and weaken the resonance of the insertion loss.

[0012] In a possible implementation manner, the shielding film fills the contact groove and contacts the ground line.

[0013] When the distance between the surface of the conductor layer and the inner surface of the shielding film on the corresponding side is small and the depth of the contact groove opened in the hot melt adhesive layer is small, the shielding film itself can be relied upon to fill the contact groove, and the shielding film can be in direct contact with the grounding wire to achieve grounding of the shielding film.

[0014] In a possible implementation manner, the contact groove is filled with a conductive medium, and two sides of the conductive medium are respectively in contact with the grounding wire and the shielding film.

[0015] When the distance between the surface of the conductor layer and the inner surface of the shielding film on the corresponding side is large and the depth of the contact groove opened in the hot melt adhesive layer is large, a conductive medium can be filled in the contact groove, and the two sides of the conductive medium are respectively in contact with the grounding wire and the shielding film to achieve grounding of the shielding film.

[0016] In a possible implementation, the shielding film includes a shielding layer, and the thickness of the shielding layer is in the range of 0.15 μm-0.55 μm.

[0017] By setting a shielding layer, the shielding layer contains a conductive material and is grounded. Thus, the electromagnetic shielding function of the flexible flat cable is realized through the shielding layer, and the shielding layer can isolate the conductor layer in the signal layer from the external electric field, so that the working performance of the conductor layer is not affected by the external electric field, and the conductor layer will not affect the external electric field.

[0018] In a possible implementation, the shielding film further includes an adhesive layer, which is attached to a side of the shielding layer facing the signal layer, and the adhesive layer is bonded and connected to the signal layer.

[0019] By setting an adhesive layer on the surface of the shielding layer facing the signal layer, the shielding film can be adhered to the surface of the signal layer by the adhesive layer. The shielding film can be first produced separately, and the shielding film as a whole can be connected to the signal layer by bonding.

[0020] In a possible implementation manner, the adhesive layer is a conductive adhesive layer, and the conductive adhesive layer is in electrical contact with each grounding line in the signal layer.

[0021] The shielding layer is grounded by setting the adhesive layer as a conductive adhesive layer that can conduct electricity and making electrical contact between the conductive adhesive layer and each grounding wire.

[0022] In a possible implementation, the adhesive layer is an insulating adhesive layer, and a plurality of avoidance openings are provided in the adhesive layer, each avoidance opening corresponds to each grounding wire in the signal layer one by one, and the shielding layer is in electrical contact with the grounding wire through the avoidance opening.

[0023] By setting the adhesive layer as an insulating adhesive layer and opening a plurality of avoidance openings in the adhesive layer so that each avoidance opening corresponds to each grounding wire one by one, the shielding layer can be electrically contacted with each grounding wire through the avoidance openings, thereby achieving grounding of the shielding layer.

[0024] In a possible implementation, the thickness of the adhesive layer is in the range of 1.5 μm to 4.5 μm.

[0025] By setting the thickness of the adhesive layer between 1.5μm-4.5μm, the adhesive layer will not be too thin, thereby ensuring that the adhesive layer is evenly attached to the surface of the shielding layer, ensuring that the hot melt adhesive layer of the adhesive layer and the signal layer are firmly and securely connected, and ensuring the stability and reliability of the connection between the shielding film and the signal layer; and, the adhesive layer will not be too thick, thereby maintaining the thickness of the shielding film within a smaller range, ensuring that the flexible flat cable has a smaller thickness as a whole.

[0026] In a possible implementation manner, the shielding layer is a conductive layer sprayed on the surface of the signal layer, or the shielding layer is a metal layer adsorbed on the surface of the signal layer.

[0027] By spraying a conductive layer on the surface of the signal layer as a shielding layer, or by adsorbing an ultra-thin metal layer (vacuum) on the surface of the signal layer, the shielding layer is directly attached to the surface of the signal layer, avoiding the need to set an adhesive layer on the surface of the shielding layer facing the signal layer, thereby reducing the overall thickness of the shielding film.

[0028] In a possible implementation manner, the shielding film further includes an insulating layer, and the insulating layer covers a side of the shielding layer facing away from the signal layer.

[0029] By covering the side of the shielding film away from the signal layer with an insulating layer, the shielding layer is prevented from being exposed to the outside world. The insulating layer provides electrostatic protection for the shielding layer, thereby preventing the shielding film from problems such as electrostatic discharge, electrostatic breakdown, and short circuit. The insulating layer can also provide physical protection for the shielding layer, preventing the shielding layer from being scratched or broken, thereby ensuring the reliability of the flexible flat cable.

[0030] In a possible implementation manner, the insulating layer is a spray layer sprayed on the surface of the shielding layer, or the insulating layer is an insulating film adhered to the surface of the shielding layer.

[0031] In a possible implementation manner, the thickness of the insulating layer ranges from 4.5 μm to 9.5 μm.

[0032] By controlling the thickness of the insulating layer between 4.5μm-9.5μm, the insulating layer has a certain thickness, which can play a protective role for the shielding layer. Moreover, the thickness of the insulating layer is small and will not significantly increase the overall thickness of the shielding film. The shielding film maintains a small thickness, which can reduce the thickness of the flexible flat cable and expand the application range of the flexible flat cable.

[0033] In a possible implementation manner, the shielding layer is a liquid metal layer.

[0034] A second aspect of the present application provides a manufacturing process for a flexible flat cable, which is used to manufacture the flexible flat cable as described above, and the manufacturing process includes:

[0035] Producing and forming a signal layer;

[0036] Shielding films are attached to both side surfaces of the signal layer in the thickness direction to form a flexible flat cable.

[0037] In a possible implementation, attaching the shielding film to the surface of the signal layer includes:

[0038] Manufacturing and forming a shielding film;

[0039] Attach the shielding film to the surface of the signal layer.

[0040] In a possible implementation manner, the shielding film includes a shielding layer and an adhesive layer attached to the surface of the shielding layer, and the manufacturing of the shielding film includes:

[0041] disposing an adhesive layer on a carrier film;

[0042] Attach the shielding layer to the adhesive layer.

[0043] In a possible implementation, attaching the shielding layer to the adhesive layer includes:

[0044] placing the shielding layer on the adhesive layer in a hot melt state to attach the shielding layer to the adhesive layer; or,

[0045] A shielding material is sprayed onto the adhesive layer to form a shielding layer on the adhesive layer.

[0046] In a possible implementation manner, the shielding film further includes an insulating layer, and after the shielding layer is attached to the adhesive layer, the shielding film further includes:

[0047] Attach the insulation to the shield.

[0048] In a possible implementation, attaching the insulating layer to the shielding layer includes:

[0049] Spraying insulating material onto the shielding layer to form an insulating layer; or,

[0050] An insulating film is attached to the shielding layer to form an insulating layer.

[0051] In a possible implementation, the signal layer includes a conductor layer and a hot melt adhesive layer, the conductor layer includes a plurality of wires, and the signal layer is formed by:

[0052] shaping a plurality of conductive wires to form a conductor layer;

[0053] A hot melt adhesive layer is wrapped around the outer periphery of the conductor layer to form a signal layer. In a possible implementation, the plurality of conductors include a plurality of signal wires and a plurality of ground wires, and the ground wires are arranged at intervals along the plane direction of the conductor layer;

[0054] After the signal layer is formed, it includes:

[0055] A plurality of contact grooves are formed on the hot melt adhesive layer, so that each contact groove corresponds to each grounding wire one by one, and the contact grooves are extended to expose the grounding wire;

[0056] The shielding film is attached to the surface of the hot melt adhesive layer so that the shielding film is in electrical contact with the grounding wire through the contact groove.

[0057] In a possible implementation manner, after the signal layer is formed and before the shielding film is attached to the surface of the signal layer, the method further includes:

[0058] Conduct electrical performance test on the signal layer;

[0059] If the electrical performance of the signal layer meets the requirements, the shielding film is attached; if the electrical performance of the signal layer does not meet the requirements, the signal layer is scrapped or reworked.

[0060] In a possible implementation manner, after the flexible flat cable is formed, the method further includes:

[0061] Conduct electrical performance tests on flexible flat cables;

[0062] If the electrical performance of the flexible flat cable meets the requirements, the flexible flat cable is subjected to final inspection; if the electrical performance of the flexible flat cable does not meet the requirements, the flexible flat cable is scrapped or reworked.

[0063] A third aspect of the present application provides an electronic device, comprising a housing assembly and the flexible flat cable as described above, wherein the flexible flat cable is located inside the housing assembly.

[0064] The electronic device provided by the present application includes a shell assembly and a flexible flat cable installed in the shell assembly, the flexible flat cable includes a signal layer and a shielding film, the signal layer is used to transmit signals, the shielding film is attached to the two side surfaces of the signal layer in the thickness direction, the shielding film is used to insulate and protect the signal layer, and can achieve electromagnetic shielding, the signal layer and the shielding films on both sides thereof together constitute a flexible flat cable, and the structure of the flexible flat cable is simple and the cost is low. Among them, by designing the shielding film, on the basis of ensuring the loss performance and controllable impedance of the flexible flat cable, the thickness of the shielding film is thinned, and the thickness of the shielding film is controlled to be between 0.5μm-12μm, thereby reducing the overall thickness of the flexible flat cable and expanding the application range of the flexible flat cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0066] Figure 2 for Figure 1 an exploded structural diagram of the electronic device shown;

[0067] Figure 3 A schematic diagram of the structure of another electronic device provided in an embodiment of the present application;

[0068] Figure 4 for Figure 3 A schematic diagram of the structure of the electronic device in the unfolded state;

[0069] Figure 5 for Figure 3 A schematic diagram of the structure of the electronic device in a folded state;

[0070] Figure 6 for Figure 3 An exploded diagram of the electronic equipment in the

[0071] Figure 7 It is a schematic diagram of the structure of a conventional flexible flat cable;

[0072] Figure 8 A schematic diagram of the structure of an insulating film on one side of a conventional flexible flat cable;

[0073] Fig. 9 This is a schematic diagram of the grounding method of a conventional flexible flat cable;

[0074] Fig.10 A flexible flat cable provided in an embodiment of the present application;

[0075] Fig.11 A comparison diagram of the flexible flat cable provided in the embodiment of the present application and a conventional flexible flat cable;

[0076] Fig.12 A schematic diagram of the structure of a shielding film in a flexible flat cable provided in an embodiment of the present application;

[0077] Fig.13 A schematic diagram of grounding of a flexible flat cable provided in an embodiment of the present application;

[0078] Fig.14a A schematic diagram of a grounding method for a flexible flat cable provided in an embodiment of the present application;

[0079] Fig.14b A schematic diagram of another grounding method for a flexible flat cable provided in an embodiment of the present application;

[0080] Fig.15a The simulation test results of the characteristic impedance of a conventional flexible flat cable;

[0081] Fig.15b The simulation test result of the characteristic impedance of the flexible flat cable of the embodiment of the present application;

[0082] Fig.15c A comparison diagram of simulation test results of characteristic impedances of the flexible flat cable according to the embodiment of the present application and a conventional flexible flat cable;

[0083] Fig.16a The simulation test results of the insertion loss of a conventional flexible flat cable are shown below;

[0084] Fig.16b The simulation test result of the insertion loss of the flexible flat cable of the embodiment of the present application;

[0085] Fig.16c A comparison chart of simulation test results of insertion loss of the flexible flat cable according to the embodiment of the present application and a conventional flexible flat cable;

[0086] Fig.17 A comparison chart of simulation test results of insertion loss indicators of the flexible flat cable of the embodiment of the present application and a conventional flexible flat cable;

[0087] Fig.18 A flowchart of the steps of the manufacturing process provided in the embodiment of the present application;

[0088] Fig.19 A flow chart of the steps for making a shielding film provided in an embodiment of the present application. DETAILED DESCRIPTION

[0089] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0090] The embodiment of the present application provides an electronic device, which can be a consumer electronic product. Exemplarily, the electronic device includes but is not limited to a mobile phone, a portable android device (PAD), a notebook computer (NoteBook Computer, referred to as NoteBook), an ultra-mobile personal computer (UMPC), a walkie-talkie, a netbook, a POS (Point of sales) machine, a personal digital assistant (PDA), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, etc.

[0091] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 1 As shown, taking the electronic device 1 as a bar-type electronic device as an example, for example, the electronic device 1 is a bar-type mobile phone, the electronic device 1 may include a housing assembly 100 and a display screen 200. One side surface of the display screen 200 is used to display image information, and this side surface of the display screen 200 is usually defined as its front side, and the other side surface opposite to its front side is its back side. The housing assembly 100 is arranged around the side and back side of the display screen 200 to support and fix the display screen 200 and provide protection. The front side of the display screen 200 is exposed outside the housing assembly 100, so that the user can view the content displayed on the display screen 200 or perform input operations on the electronic device 1.

[0092] Taking the straight-type electronic device shown in the figure as an example, the display screen 200 of the electronic device 1 may be a rigid screen, and the display screen 200 may be an LCD (Liquid Crystal Display) display screen or an OLED (Organic Light-Emitting Diode) display screen.

[0093] Figure 2 for Figure 1 An exploded view of the electronic device is shown. Figure 2As shown, taking a straight-type electronic device as an example, the housing assembly 100 of the electronic device 1 may include a middle frame 110 and a back cover 120, wherein the middle frame 110 is connected between the display screen 200 and the back cover 120, the display screen 200 is supported on one side surface of the middle frame 110, and the back cover 120 is connected to the other side surface of the middle frame 110. The display screen 200 is usually mounted on the middle frame 110 as a whole to ensure the strength and stability of the display screen 200 and meet the use requirements of the display screen 200. The back cover 120 is usually connected to the middle frame 110 in an overlapping manner, and the middle frame 110 and the back cover 120 together form a receiving cavity, and the receiving cavity is used to install components such as a circuit board 300, a battery 400, a camera 500, and a microphone (not shown in the figure).

[0094] The middle frame 110 may include a middle plate portion 111 and a frame portion 112. The middle plate portion 111 is located between the display screen 200 and the back cover 120, and is usually arranged parallel to the display screen 200 and the back cover 120. The frame portion 112 is arranged around the periphery of the middle plate portion 111. The frame portion 112 may, for example, extend perpendicular to the plate surface of the middle plate portion 111 to both sides of the middle plate portion 111. Exemplarily, the frame portion 112 and the middle plate portion 111 may be an integrally formed structure.

[0095] The display screen 200 is usually mounted on the middle plate portion 111 of the middle frame 110 in an integrally bonded manner. For example, the display screen 200 is bonded to the middle plate portion 111 as a whole. The support of the middle plate portion 111 on the display screen 200 can ensure that the display screen 200 is supported stably and firmly, so that the display screen 200 has sufficient strength to meet the use requirements of the display screen 200 being frequently pressed. The frame portion 112 is arranged around the side of the display screen 200 to protect the side of the display screen 200, help the display screen 200 resist risk scenarios such as collision and falling, and protect the display screen 200 from damage.

[0096] The edge of the back cover 120 is connected to the frame portion 112 of the middle frame 110, for example, the edge of the back cover 120 is bonded to the frame portion 112. There is a gap between the middle plate portion 111 of the middle frame 110 and the back cover 120, and the gap forms a receiving cavity as described above, so that a device can be installed in the receiving cavity between the middle plate portion 111 of the middle frame 110 and the back cover 120.

[0097] Figure 3 A schematic diagram of the structure of another electronic device provided in an embodiment of the present application; Figure 4 for Figure 3 A schematic diagram of the structure of the electronic device in the unfolded state; Figure 5 for Figure 3 Schematic diagram of the structure of the electronic device in a folded state.

[0098] Reference Figures 3 to 5As shown, taking the electronic device 1 as a foldable electronic device as an example, for example, the electronic device 1 is a foldable mobile phone, the electronic device 1 may include at least two parts that can rotate relative to each other, and the electronic device 1 may have different usage states in different usage scenarios. In this embodiment, taking the foldable electronic device as an electronic device 1 that can be folded once as an example, the electronic device 1 includes two parts that can rotate relative to each other, and the usage state of the electronic device 1 is changed by the relative rotation of the two parts.

[0099] The two parts of the electronic device 1 can be along Figure 3 When the two parts are rotated to overlap each other, the electronic device 1 is in a Figure 4 In the folded state shown in FIG. 1 , the electronic device 1 is small in size and easy to carry; the two parts of the electronic device 1 can also be moved along the same Figure 3 The electronic device 1 is in a state where the two parts rotate relative to each other in the direction opposite to the direction of the arrows in the figure. When the two parts rotate to be coplanar, the electronic device 1 is in a state where the two parts rotate relative to each other in the direction opposite to the direction of the arrows in the figure. Figure 5 In the unfolded state shown in FIG, the unfolding angle α of the electronic device 1 is, for example, 180°, at which time the electronic device 1 can realize a large screen display; in some cases, the electronic device 1 can also be kept in a semi-expanded state (see Figure 3 As shown), at this time, the electronic device 1 is suspended at a certain angle between the unfolded state and the folded state. Exemplarily, the suspension angle β of the electronic device 1 can be 120°, 130°, 140° or 150°, etc.

[0100] It should be noted that the angles illustrated in this embodiment are all allowed to have a slight deviation. For example, the unfolding angle α of the electronic device 1 is 180°, which means that the unfolding angle α can be 180°, or about 180°, such as 170°, 175°, 185° or 190°. The angles illustrated in the following text can be understood in the same way.

[0101] In addition, in addition to the electronic device 1 that can be folded once, the electronic device 1 can also be an electronic device 1 that can be folded more than twice. In this case, the electronic device 1 can include multiple parts that are connected by rotating in sequence, and two adjacent parts can be relatively close to each other to be folded to a folded state, and the two adjacent parts can also be relatively far apart to be unfolded to an unfolded state.

[0102] Figure 6 for Figure 3 Exploded diagram of the electronic equipment in the . Figure 6 As shown, for a foldable electronic device, the electronic device 1 may also include a shell assembly 100 and a display screen 200. The front of the display screen 200 is used to display image information. The shell assembly 100 is arranged around the sides and back of the display screen 200 to support and fix the display screen 200 and provide protection, which will not be repeated here.

[0103] The display screen 200 of the foldable electronic device may include a foldable first display screen 200a, and the first display screen 200a may include a first area 210, a second area 220, and a bendable area 230, wherein the bendable area 230 is located between the first area 210 and the second area 220. During use of the electronic device 1, the first area 210 and the second area 220 always maintain a planar state, and the bendable area 230 may be bent to change the angle between the first area 210 and the second area 220, so that the first display screen 200a is folded or unfolded with the movement of the housing assembly 100, so that the electronic device 1 can be switched between a folded state and an unfolded state.

[0104] Exemplarily, in the first display screen 200a, at least the bendable area 230 is made of a flexible material so that the bendable area 230 is bendable. The first area 210 and the second area 220 can be made of a flexible material, or a rigid material, or partially made of a rigid material and partially made of a flexible material, which is not limited in this embodiment.

[0105] The first display screen 200a includes but is not limited to an organic light-emitting diode (OLED) display screen, an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (AMOLED) display screen, a mini organic light-emitting diode (MID) display screen, a micro organic light-emitting diode (MID) display screen, a micro organic light-emitting diode (MID) display screen, or a quantum dot light emitting diode (QLED) display screen, etc.

[0106] Among them, combined Figure 4 and Figure 6 As shown, when the first display screen 200a is in a folded state, the first area 210 and the second area 220 are relatively stacked, and the bendable area 230 is in a bent state. The bending angle of the bendable area 230 is, for example, 180°. At this time, the electronic device 1 is small in size and easy to carry and store. Figure 5 and Figure 6As shown, when the first display screen 200a is in the unfolded state, the first area 210 and the second area 220 are in a relatively far unfolded state, the bendable area 230 is in a flattened state without bending, and the first area 210, the second area 220 and the bendable area 230 face the same direction and are in a coplanar state. At this time, the angle between the first area 210 and the second area 220 is 180°, and the first display screen 200a can achieve large-screen display, giving users a better user experience.

[0107] It should be noted that the figure takes the foldable electronic device as an inner foldable structure as an example. When the electronic device 1 is in the folded state, the first area 210 and the second area 220 of the first display screen 200a are relatively fitted, and the housing assembly 100 is arranged outside the first display screen 200a to prevent the first display screen 200a from being scratched by hard objects. Figure 4 If the inward-folding electronic device needs to realize the display function in the folded state, a second display screen 200b can be added to the back of the shell assembly 100. When the electronic device 1 is in the folded state, the display function is realized by the second display screen 200b.

[0108] In other words, the display screen 200 of the inward-folding electronic device may include a first display screen 200a and a second display screen 200b. The first display screen 200a may be a folding screen installed on the front of the shell assembly 100, and the first display screen 200a may be switched between an unfolded state and a folded state. The second display screen 200b may be a single screen installed on the back of the shell assembly 100, and the second display screen 200b is displayed when the electronic device 1 is in a folded state.

[0109] In other examples, the foldable electronic device may also be an external foldable structure. When the electronic device 1 is in the folded state, the first area 210 and the second area 220 of the first display screen 200a are opposite to each other, the housing assembly 100 is located between the first area 210 and the second area 220, and the first display screen 200a is surrounded outside the housing assembly 100. The first display screen 200a is exposed to the outside and visible to the user. The first display screen 200a can be used to realize the display function, so there is no need to add the second display screen 200b on the back of the housing assembly 100. In other words, the external foldable electronic device may only include the first display screen 200a installed on the front of the housing assembly 100.

[0110] In addition, combined Figure 3 and Figure 6As shown, in some embodiments, the foldable electronic device, especially the inward-folding electronic device, can rely on the damping force provided by the housing assembly 100 to make the electronic device 1 hover at a certain angle between the unfolded state and the folded state, that is, the electronic device 1 is in a semi-expanded state, at which time, the bendable area 230 of the first display screen 200a is also in a bent state, and the first area 210 and the second area 220 of the first display screen 200a are relatively inclined. For example, the hovering angle of the electronic device 1 is 120°, 130°, 140° or 150°, etc., and accordingly, the angle between the first area 210 and the second area 220 can be 120°, 130°, 140° or 150°, etc.

[0111] For a foldable electronic device, the housing assembly 100 not only supports and fixes the first display screen 200a, but also needs to drive the first display screen 200a to switch between a folded state and an unfolded state. Figure 6 As shown, the housing assembly 100 of the foldable electronic device may include a first middle frame 110a, a second middle frame 110b and a hinge 130, wherein the hinge 130 is connected between the first middle frame 110a and the second middle frame 110b, and the first middle frame 110a and the second middle frame 110b are rotatably connected via the hinge 130, thereby realizing relative rotation between the first middle frame 110a and the second middle frame 110b.

[0112] The first middle frame 110a supports and fixes the first area 210 of the first display screen 200a, and the second middle frame 110b supports and fixes the second area 220 of the first display screen 200a. In other words, the first area 210 of the first display screen 200a can be mounted on the first middle frame 110a, and the second area 220 of the first display screen 200a can be mounted on the second middle frame 110b. The bendable area 230 of the first display screen 200a is arranged corresponding to the rotating shaft 130. When the rotating shaft 1301 drives the first middle frame 110a and the second middle frame 110b to rotate relative to each other, the first area 210 and the second area 220 of the first display screen 200a change their orientation accordingly, and the bendable area 230 of the first display screen 200a bends or flattens as the orientation of the first area 210 and the second area 220 changes.

[0113] Specifically, the first middle frame 110a and the second middle frame 110b can be rotated in a direction close to each other until the two are relatively stacked. At this time, the housing assembly 100 is in a folded state, and the first display screen 200a is in a folded state along with the folding of the housing assembly 100. Figure 4 As shown; the first middle frame 110a and the second middle frame 110b can also be rotated in a direction away from each other until the two are coplanar. At this time, the housing assembly 100 is in an unfolded state, and the first display screen 200a is in an unfolded state with the unfolding of the housing assembly 100, as shown Figure 5As shown; the first middle frame 110a and the second middle frame 110b can also rotate relative to each other until they stay between the folded state and the unfolded state. At this time, the shell assembly 100 is in a semi-expanded state (hovering state), and the angle between the first middle frame 110a and the second middle frame 110b is, for example, 120°, 130°, 140° or 150°, etc., and the first display screen 200a is in a semi-expanded state with the shell assembly 100.

[0114] Continue to refer to Figure 6 As shown, the first display screen 200a can be integrally mounted on one side of the first middle frame 110a and the second middle frame 110b. For an inward-folding electronic device with an additional second display screen 200b, taking the second display screen 200b mounted on the side where the second middle frame 110b is located as an example, the second display screen 200b can be installed on the other side of the second middle frame 110b, and the housing assembly 100 further includes a first back cover 120a, which is connected to the other side of the first middle frame 110a. For an outward-folding electronic device or an inward-folding electronic device without an additional second display screen 200b, the electronic device 1 may further include a first back cover 120a and a second back cover 120b, which is connected to the other side of the first middle frame 110a and the second back cover 120b is connected to the other side of the second middle frame 110b.

[0115] The first middle frame 110a and the first back cover 120a together form a first receiving cavity, the second middle frame 110b and the second display screen 200b (second back cover 120b) form a second receiving cavity, and the internal components of the electronic device 1 can be installed in the first receiving cavity and the second receiving cavity, respectively. For example, a circuit board 300 can be installed in both the first receiving cavity and the second receiving cavity, and other components such as a battery 400 and a camera 500 can also be installed in at least one of the first receiving cavity and the second receiving cavity, and these components can be installed on the first middle frame 110a and the second middle frame 110b.

[0116] As for the electrical connection between the components in the electronic device 1, since certain errors are inevitable during the production and installation of the components, in order to eliminate the influence of the errors of the components and ensure reliable connection between the components, flexible electrical connectors are usually used to connect the corresponding components with spacing, and the bendable and deformable properties of the flexible electrical connectors are utilized to meet the requirements of the spacing, relative position, etc. of the component installation.

[0117] Flexible Flat Cable (FFC) is a flexible electrical connector, consisting of two layers of insulating film with a flat copper foil sandwiched between them. It has a simple structure and low cost. In addition, the insulating films on both sides of the flexible flat cable can play the role of electromagnetic shielding, which can improve the loss performance of the flexible flat cable. Therefore, the application of flexible flat cables in consumer electronic products is becoming more and more widespread.

[0118] Figure 7 This is a schematic diagram of the structure of a conventional flexible flat cable. Figure 7 As shown, a conventional flexible flat cable 600a is composed of a signal transmission layer 610a and an insulating film 620a attached to both sides of the signal transmission layer 610a. The middle signal transmission layer 610a is composed of a plurality of (flat) copper foils 611a arranged at intervals along its plane direction and a hot melt adhesive layer 612a attached to the outer periphery of the copper foil 611a. The copper foil 611a is used to generate current and transmit signals, and the hot melt adhesive layer 612a is used to position and protect the copper foil 611a and to achieve the bonding of the signal transmission layer 610a and the insulating film 620a. The single-sided insulating film 620a includes a first insulating layer 621a, an adhesive layer 622a, an aluminum layer 623a and a second insulating layer 624a which are sequentially arranged on the surface of the hot-melt adhesive layer 612a. The first insulating layer 621a serves as a basic supporting layer to facilitate the formation of the insulating film 620a and the connection between the insulating film 620a and the hot-melt adhesive layer 612a. The adhesive layer 622a is used to bond the shielding layer to the first insulating layer 621a. The aluminum layer 623a is used to achieve electromagnetic shielding. The second insulating layer 624a is used to insulate and protect the aluminum layer 623a.

[0119] Exemplarily, in the insulating film 620a, the first insulating layer 621a and the second insulating layer 624a can both be PET (Polyethylene terephthalate) layers or PP (Polypropylene) layers, the adhesive layer 622a can be an ADH (Adipic acid dihydrazide) layer, and the aluminum layer 623a and the second insulating layer 624a (PET layer or PP layer) together constitute aluminum foil Mylar.

[0120] It can be seen that the stacking method of the conventional flexible flat cable 600a is relatively complicated. The flexible flat cable 600a is provided with insulating films 620a on both sides. The insulating film 620a on one side includes a first insulating layer 621a, an adhesive layer 622a, an aluminum layer 623a and a second insulating layer 624a stacked in sequence. The thickness of these structural layers of the insulating film 620a is relatively large, which leads to a large thickness of the insulating film 620a on one side. Therefore, the overall thickness of the flexible flat cable 600a formed after the insulating films 620a on both sides are bonded with the middle signal transmission layer 610a is relatively large.

[0121] When manufacturing a conventional flexible flat cable 600a, the signal transmission layer 610a and the complete insulating film 620a are usually separately manufactured first, and then the insulating film 620a is integrally bonded to both sides of the signal transmission layer 610a to form a complete flexible flat cable 600a. Figure 8A schematic diagram of the structure of the insulating film on one side of a conventional flexible flat cable, see Figure 8 As shown, for the insulating film 620a formed separately, the insulating film 620a can be formed on a release film 6201a, and a layer of adhesive layer 6202a (such as the aforementioned ADH layer) is coated on the release film 6201a, and a first insulating layer 621a, an adhesive layer 622a, an aluminum layer 623a and a second insulating layer 624a are sequentially adhered to the release film 6201a.

[0122] like Figure 8 As shown, for example, the thickness of the release film 6201a can be 0.036mm, the thickness of the adhesive layer 6202a can be 0.03mm, the thickness of the first insulating layer 621a can be 0.04mm, the thickness of the bonding layer 622a can be 0.03mm, and the thickness of the aluminum foil Mylar formed by the aluminum layer 623a and the second insulating layer 624a can be 0.1mm. Before the insulating film 620a is attached to the signal transmission layer 610a, the release film 6201a will be torn off (it may take away part of the thickness of the adhesive layer 6202a), and the release film 6201a is not included in the total thickness of the insulating film 620a. The total thickness of the insulating film 620a is calculated based on the aluminum foil Mylar formed by the adhesive layer 6202a, the first insulating layer 621a, the bonding layer 622a, the aluminum layer 623a, and the second insulating layer 624a, and the total thickness of the insulating film 620a reaches 0.2mm. Therefore, the overall thickness of the flexible flat cable 600a can generally reach about 0.4 mm to 0.5 mm.

[0123] Due to the large thickness of the conventional flexible flat cable 600a, the application scenarios of the flexible flat cable 600a are limited under the trend of gradually becoming thinner and lighter consumer electronic products. In the field of consumer electronic products, the most commonly used scenario for the flexible flat cable 600a is on PC (Personal Computer) products, and the flexible flat cable 600a has been used as the main way to transmit high-speed signals such as USB3.2. In some non-bending scenarios or static bending scenarios, when the height space (spatial distance in the thickness direction) in the electronic device reaches 0.4mm, the flexible flat cable 600a is widely used, for example, the flexible flat cable 600a transmits USB3.2 signals across the fan, the flexible flat cable 600a of the MIC (microphone) device, the flexible flat cable 600a of the Hall (Hall) device, and the flexible flat cable 600a of some Cam (camera) devices, etc.

[0124] However, although the flexible flat cable 600a (FFC) has low cost and good loss performance, its large thickness restricts its application in electronic products with limited thickness. Flexible printed circuit (FPC), which has similar functions and application scenarios to the flexible flat cable 600a, has more application scenarios in mobile phones, PADs (portable android devices, tablet computers) and PC products due to its relatively thin thickness (the overall thickness of FPC is generally around 0.15mm to 0.25mm).

[0125] In the case where the height space in the electronic device is severely limited, for example, when the height space in the electronic device is within 0.3 mm, only FPC can be used, and the flexible flat cable 600a cannot be used. For example, the flexible flat cable 600a cannot be used under the fan of a PC product, above or below the battery of a mobile phone or PAD, etc.

[0126] In addition, for the conventional flexible flat cable 600a, if the thickness of the hot melt adhesive layer 612a or the first insulating layer 621a, the adhesive layer 622a and other structural layers is forcibly thinned, although the overall thickness of the flexible flat cable 600a can be reduced to a certain extent, it will cause the distance between the copper foil 611a and the aluminum layer 623a (reference stratum) to become smaller, thereby causing the characteristic impedance of the flexible flat cable 600a to decrease, resulting in the signal quality of the flexible flat cable 600a to deteriorate.

[0127] As for the conventional grounding method of the flexible flat cable 600a, refer to Fig. 9 As shown in the figure, a conventional grounding method of a flexible flat cable is schematically shown. When a conventional flexible flat cable 600a is designed, among the multiple copper foils 611a arranged in sequence along the plane direction in the signal transmission layer 610a, the middle copper foils 611a are all used as signal lines for signal transmission, and only the copper foils 611a arranged at both ends of the flexible flat cable 600a in the length direction are used as grounding wires 6111a. The grounding wires 6111a at both ends are respectively connected to corresponding gold fingers 601a at both ends of the flexible flat cable 600a (the flexible flat cable 600a is connected to a device (such as a connector) through the gold fingers 601a arranged at both ends), and by setting a flange on the corresponding gold finger 601a, the corresponding gold finger 601a is folded to contact the aluminum layer 623a in the insulating film 620a to achieve grounding of the aluminum layer 623a.

[0128] However, when the length of the flexible flat cable 600a is long, the grounding parts that only exist at the two ends of the flexible flat cable 600a (in the length direction) will lead to poor grounding effect of the flexible flat cable 600a, and the resulting insertion loss (the loss of energy or gain when a device or branch circuit is added to a circuit) is prone to strong resonance, resulting in poor signal quality of the flexible flat cable 600a.

[0129] In view of this, the embodiment of the present application improves the flexible flat cable, which includes a signal layer and a shielding film. The signal layer is used to transmit signals. The shielding film is attached to the two side surfaces of the signal layer in the thickness direction. The shielding film is used to insulate and protect the signal layer and can achieve electromagnetic shielding. The signal layer and the shielding films on both sides together constitute a flexible flat cable. The structure of the flexible flat cable is simple and the cost is low. Among them, by designing the shielding film, the thickness of the shielding film is thinned on the basis of ensuring the loss performance and controllable impedance of the flexible flat cable, and the thickness of the shielding film is controlled to be between 0.5μm-12μm, thereby reducing the overall thickness of the flexible flat cable and expanding the application range of the flexible flat cable.

[0130] The flexible flat cable according to the embodiment of the present application is described in detail below.

[0131] Fig.10 The flexible flat cable provided in the embodiment of the present application. Fig.10 As shown, the flexible flat cable 600 of this embodiment includes a signal layer 610 and a shielding film 620. The signal layer 610 is used to flow current to transmit signals. The shielding film 620 is attached to the two side surfaces of the signal layer 610 in the thickness direction. The setting of the shielding film 620 can improve the structural strength of the flexible flat cable 600 and ensure the stability and reliability of the flexible flat cable 600. In addition, the shielding film 620 also plays a physical protection role for the signal layer 610, which can prevent the signal layer 610 from being scratched or broken, and ensure the stable operation of the signal layer 610. More importantly, the shielding film 620 insulates and isolates the signal layer 610 from the outside world, and can achieve electromagnetic shielding, prevent the flexible flat cable 600 from electrostatic discharge (ESD), short circuit due to electrostatic breakdown, and other problems, and ensure the loss performance of the flexible flat cable 600.

[0132] Among them, the signal layer 610 includes a conductor layer 611 and a hot melt adhesive layer 612, the hot melt adhesive layer 612 is attached to the conductor layer 611, and the hot melt adhesive layer 612 is wrapped around the periphery of the conductor layer 611, and the shielding film 620 is attached to the two side surfaces of the hot melt adhesive layer 612 in the thickness direction. The conductor layer 611 is a metal layer, and the conductor layer 611 is used to allow current to pass through to transmit signals. The hot melt adhesive layer 612 wrapped outside the conductor layer 611 can protect the conductor layer 611 from external damage, ensure that the conductor layer 611 transmits signals reliably and stably, and the hot melt adhesive layer 612 can also be used to achieve the connection between the signal layer 610 and the shielding film 620.

[0133] Exemplarily, a hot pressing process may be used to attach the shielding film 620 to the hot melt adhesive layer 612 when the hot melt adhesive layer 612 is in a hot melt state. After the hot melt adhesive layer 612 is cured, the shielding film 620 and the hot melt adhesive layer 612 are firmly and securely connected.

[0134] In the flexible flat cable 600 of the present embodiment, the overall thickness of the signal layer 610 can be maintained unchanged. In other words, the thickness of the hot melt adhesive layer 612 wrapped around the outer periphery of the conductor layer 611 can be consistent with the thickness of the hot melt adhesive layer 612a of the conventional flexible flat cable 600a. In this way, the shielding film 620 and the conductor layer 611 are separated by a hot melt adhesive layer 612 of sufficient thickness, which can ensure that there is a sufficient distance between the shielding film 620 (the reference ground layer therein) and the conductor layer 611, and the characteristic impedance of the flexible flat cable 600 can be controlled within a reasonable range, thereby ensuring the signal quality of the flexible flat cable 600.

[0135] On the basis of ensuring that the impedance of the flexible flat cable 600 is controllable, this embodiment designs the shielding film 620 of the flexible flat cable 600, mainly designs the film layer structure of the shielding film 620. On the premise that the shielding film 620 can achieve the electromagnetic shielding function, the thickness of the shielding film 620 is thinned, and the thickness of the shielding film 620 is controlled between 0.5μm and 12μm, thereby reducing the overall thickness of the flexible flat cable 600 and expanding the application scope of the flexible flat cable 600.

[0136] Exemplarily, the thickness of the shielding film 620 may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, etc.

[0137] Fig.11 This is a comparison diagram of the flexible flat cable provided in the embodiment of the present application and a conventional flexible flat cable. Fig.11As shown, taking the thickness of the insulating film 620a of the conventional flexible flat cable 600a as 0.2mm as an example, in this embodiment, by controlling the thickness of the shielding film 620 to be between 0.5μm and 12μm, the thickness of the shielding film 620 is reduced by a thickness △h of 188μm to 199.5μm compared with the conventional solution, or in other words, the range of △h is 0.188mm to 0.1995mm. It can be understood that since the flexible flat cable 600 is generally a double-shielded structure, in other words, the shielding film 620 is provided on both sides of the signal layer 610 of the flexible flat cable 600, and the overall thickness of the flexible flat cable 600 is reduced by 2△h, that is, the overall thickness of the flexible flat cable 600 is reduced by 2△h in the range of 0.376mm to 0.399mm.

[0138] Calculated based on the minimum value of 0.188mm for the reduced thickness △h of the shielding film 620, the overall reduced thickness 2△h of the flexible flat cable 600 is 0.376mm. Compared with the conventional flexible flat cable 600a, the thickness of the flexible flat cable 600 of this embodiment is significantly reduced. Taking the conventional flexible flat cable 600a having a thickness of 0.5mm as an example, and taking the overall reduced thickness 2△h of the flexible flat cable 600 of this embodiment as 0.376mm as an example, the thickness of the improved flexible flat cable 600 of this embodiment can be reduced to 0.124mm, which is comparable to the thickness of a conventional FPC (flexible circuit board) (the thickness of the flexible flat cable 600 of this embodiment is even slightly less than that of a conventional FPC).

[0139] Therefore, the flexible flat cable 600 of this embodiment has a wider range of application scenarios while ensuring loss performance and controllable impedance. For example, the flexible flat cable 600 of this embodiment can be used under the fan of mobile phones and PC products and above and below the battery of PADs.

[0140] Fig.12 A schematic diagram of the structure of a shielding film in a flexible flat cable provided in an embodiment of the present application. Fig.12 As shown, the shielding film 620 at least includes a shielding layer 621, and the shielding layer 621 contains a conductive material, for example, the shielding layer 621 contains a metal material, and the shielding layer 621 is grounded. Therefore, the shielding layer 621 has an electromagnetic shielding effect, and can achieve the isolation of the conductor layer 611 in the signal layer 610 and the external electric field, so that the working performance of the conductor layer 611 is not affected by the external electric field, and the conductor layer 611 will not affect the external electric field.

[0141] Exemplarily, the thickness of the shielding layer 621 may range from 0.15 μm to 0.55 μm. In other words, the thickness of the shielding layer 621 may be between 0.15 μm and 0.55 μm. For example, the thickness of the shielding layer 621 is 0.20 μm, 0.25 μm, 0.30 μm, 0.35 μm, 0.40 μm, 0.45 μm, etc.

[0142] In some embodiments, the shielding film 620 can be adhered to the surface of the signal layer 610 by bonding. In this case, the shielding film 620 can also include an adhesive layer 622, which is attached to the side surface of the shielding layer 621 facing the signal layer 610. The shielding film 620 is adhered and connected to the signal layer 610 through the adhesive layer 622.

[0143] At this time, the shielding layer 621 can be a metal layer, and the metal layer is attached to the adhesive layer 622. For example, the shielding layer 621 can be a metal layer such as a silver layer, a gold layer or an aluminum layer. Alternatively, the shielding layer 621 can also be a liquid metal layer. In other words, the shielding layer 621 is composed of an amorphous, flowable liquid metal. The liquid metal can be filled in the fixing box, and the liquid metal flows with the deformation of the flexible flat cable 600. For example, when the flexible flat cable 600 is unfolded, the liquid metal layer is flattened to achieve an electromagnetic shielding effect.

[0144] When the shielding film 620 has an adhesive layer 622, and the shielding film 620 is connected to the signal layer 610, the shielding film 620 as a whole can be first manufactured, and then the shielding film 620 as a whole is attached to the two side surfaces in the thickness direction of the signal layer 610 to form the flexible flat cable 600. Exemplarily, a hot pressing process can be used to bond the adhesive layer 622 of the shielding film 620 to the hot melt adhesive layer 612 when the hot melt adhesive layer 612 of the signal layer 610 is in a hot melt state, and after the hot melt adhesive layer 612 is cured, the adhesive layer 622 of the shielding film 620 is firmly and securely connected to the hot melt adhesive layer 612.

[0145] When making the shielding film 620, the adhesive layer 622 can be first set on the carrier film (used only as a temporary carrier of the shielding film 620), and then the shielding layer 621 is attached to the adhesive layer 622. After the shielding film 620 is formed and before the shielding film 620 and the signal layer 610 are connected, the carrier film is torn off the shielding film 620 to expose the adhesive layer 622 on one side surface of the shielding film 620 to facilitate the fitting of the shielding film 620 and the signal layer 610.

[0146] The thickness of the adhesive layer 622 can range from 1.5 μm to 4.5 μm, or in other words, the thickness of the adhesive layer 622 can be between 1.5 μm and 4.5 μm. In this way, the adhesive layer 622 is not too thin, and a uniform adhesive layer 622 can be attached to the surface of the shielding layer 621, which can ensure that the adhesive layer 622 is stably and firmly connected to the hot melt adhesive layer 612 of the signal layer 610, thereby ensuring the stability of the connection between the shielding film 620 and the signal layer 610, and ensuring the overall reliability of the flexible flat cable 600 formed. In addition, the adhesive layer 622 is not too thick, and will not have a significant impact on the total thickness of the shielding film 620, and can keep the thickness of the shielding film 620 within a relatively small range, thereby ensuring that the flexible flat cable 600 as a whole has a relatively small thickness, so as to expand the application range of the flexible flat cable 600.

[0147] Illustratively, the thickness of the adhesive layer 622 may be 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, 3.0 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4.0 μm, 4.2 μm, 4.4 μm, etc.

[0148] As an example, the adhesive layer 622 can be a conductive adhesive layer 6221, so that the adhesive layer 622 can be conductive. The shielding layer 621 located on the side of the adhesive layer 622 away from the signal layer 610 can use the adhesive layer 622 as a conductive medium 6122 to electrically contact the conductor layer 611 in the signal layer 610, thereby achieving grounding of the shielding layer 621 so that the shielding layer 621 can play an electromagnetic shielding role.

[0149] As another example, the adhesive layer 622 may also be an insulating adhesive layer, for example, the adhesive layer 622 is the aforementioned ADH layer. In this case, the adhesive layer 622 is non-conductive, and the shielding layer 621 located on the side of the adhesive layer 622 away from the signal layer 610 needs to cross the adhesive layer 622 and electrically contact the conductor layer 611 in the signal layer 610, so as to ground the shielding layer 621 and realize the electromagnetic shielding function of the shielding layer 621.

[0150] Of course, in other embodiments, the shielding layer 621 may also be directly attached to the surface of the hot melt adhesive layer 612 of the signal layer 610. For example, the shielding layer 621 may be sprayed on the surface of the hot melt adhesive layer 612, or the shielding layer 621 is a sprayed layer attached to the surface of the hot melt adhesive layer 612, or the shielding layer 621 may be a conductive layer sprayed on the surface of the hot melt adhesive layer 612; or an ultra-thin metal layer (metal film) may be used as the shielding layer 621, and the shielding layer 621 may be attached to the surface of the hot melt adhesive layer 612 by (vacuum) adsorption; or the shielding layer 621 may also be the aforementioned liquid metal layer, and the liquid metal layer is attached to the surface of the hot melt adhesive layer 612 by a fixing box.

[0151] Exemplarily, a dispensing process can be used to spray conductive silver paste onto the surface of the hot melt adhesive layer 612, and the conductive layer formed by the conductive silver paste is the shielding layer 621; the ultra-thin metal layer (metal film) is, for example, an ultra-thin and flexible copper foil, silver foil, gold foil, etc., and the ultra-thin and flexible metal foil is directly attached to the surface of the hot melt adhesive layer 612 by vacuum adsorption or the like.

[0152] By directly attaching the shielding layer 621 to the surface of the hot melt adhesive layer 612, it is avoided to set the adhesive layer 622 on the side of the shielding layer 621 facing the signal layer 610, so that the overall thickness of the shielding film 620 can be further reduced, and then the overall thickness of the flexible flat cable 600 can be reduced, which helps to achieve ultra-thin flexible flat cable 600 and enrich the application scenarios of flexible flat cable 600.

[0153] Regardless of whether the shielding layer 621 is attached with an adhesive layer 622 on the side facing the hot melt adhesive layer 612, the shielding film 620 is adhered to the surface of the hot melt adhesive layer 612 through the adhesive layer 622, or the shielding layer 621 is directly attached to the surface of the hot melt adhesive layer 612, the shielding film 620 does not include the adhesive layer 622. In order to enhance the protective effect of the shielding film 620, an insulating layer 623 can be provided on the side of the shielding layer 621 away from the signal layer 610, and the insulating layer 623 covers the shielding layer 621, which is equivalent to the insulating layer 623 being located at the outermost layer of the flexible flat cable 600.

[0154] By covering the surface of the shielding layer 621 on the side away from the signal layer 610 with an insulating layer 623, on the one hand, the insulating layer 623 plays a role in electrostatic protection for the shielding layer 621, avoiding problems such as electrostatic discharge, electrostatic breakdown, and short circuit that may be caused by the shielding layer 621 being exposed to the outside world, thereby ensuring the working performance of the flexible flat cable 600; on the other hand, the insulating layer 623 also plays a role in physical protection for the shielding layer 621, which can prevent the shielding layer 621 from being scratched or broken, thereby improving the reliability of the flexible flat cable 600 and extending the service life of the flexible flat cable 600.

[0155] When the shielding film 620 further includes an insulating layer 623, in order to keep the shielding film 620 at a relatively small thickness, the thickness of the insulating layer 623 can be controlled within a range of 4.5 μm-9.5 μm. In other words, the thickness of the insulating layer 623 is within a range of 4.5 μm-9.5 μm. In this way, the insulating layer 623 has a certain thickness, and on the basis of providing electrostatic protection and physical protection to the shielding layer 621, the thickness of the insulating layer 623 is relatively small, and the thickness of the shielding film 620 is not significantly increased. The overall thickness of the shielding film 620 is relatively small, and thus the overall thickness of the flexible flat cable 600 can be reduced, and the application range of the flexible flat cable 600 can be expanded.

[0156] Illustratively, the thickness of the insulating layer 623 may be 5.0 μm, 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, 8.5 μm, 9.0 μm, etc.

[0157] In order to obtain an insulating layer 623 with a smaller thickness, in some embodiments, a layer of insulating material may be sprayed on the surface of the shielding layer 621 to form the insulating layer 623, that is, the insulating layer 623 is a sprayed layer sprayed on the surface of the shielding layer 621; for example, the insulating layer 623 may be an ink layer sprayed on the surface of the shielding layer 621. In other embodiments, a very thin insulating film may be attached to the shielding layer 621 to form the insulating layer 623, that is, the insulating layer 623 is an insulating film attached to the surface of the shielding layer 621; for example, the insulating layer 623 may be a very thin PET film or PP film attached to the surface of the shielding layer 621.

[0158] It should be noted that when the shielding film 620 includes an adhesive layer 622, a shielding layer 621 and an insulating layer 623 stacked in sequence, the thickness of the shielding layer 621 can be smaller so that the shielding film 620 as a whole maintains a smaller thickness. For example, the thickness of the shielding layer 621 can be between 0.15μm and 0.3μm; when the shielding film 620 includes a shielding layer 621 and an insulating layer 623 stacked in sequence, or the shielding film 620 only includes a shielding layer 621, the thickness of the shielding layer 621 can be slightly larger to ensure the overall reliability of the flexible flat cable 600. For example, the thickness of the shielding layer 621 can be between 0.3μm and 0.55μm.

[0159] Fig.13 A schematic diagram of the grounding of a flexible flat cable provided in an embodiment of the present application. Fig.10 and Fig.13 As shown, in the signal layer 610 of the flexible flat cable 600 of this embodiment, the conductor layer 611 includes a plurality of wires 6111 arranged in sequence along its planar direction, the plurality of wires 6111 include a plurality of signal wires 61111 and a plurality of ground wires 61112, the plurality of signal wires 61111 can extend along the planar direction of the conductor layer, the signal wires 61111 are used to transmit signals, the plurality of ground wires 61112 are used to electrically contact the shielding film 620, and each ground wire 61112 is specifically used to electrically contact the shielding layer 621 in the shielding film 620 to realize the electromagnetic shielding function of the shielding layer 621.

[0160] Since the shielding film 620 of the flexible flat cable 600 of this embodiment is relatively thin, it is convenient for the conductor layer 611 to be in electrical contact with the shielding layer 621 in the shielding film 620. Fig.13As shown, in this embodiment, a plurality of grounding wires 61112 are arranged in the conductor layer 611, and the plurality of grounding wires 61112 are arranged at intervals along the plane direction of the conductor layer 611, and each grounding wire 61112 is electrically in contact with the shielding layer 621 in the shielding film 620. Exemplarily, the plurality of grounding wires 61112 may include grounding wires 61112 located at both ends of the length direction of the flexible flat cable 600 (contacting the corresponding end gold fingers 601), and a plurality of grounding wires 61112 sequentially arranged between the grounding wires 61112 at both ends.

[0161] By setting multiple grounding wires 61112 in the conductor layer 611, grounding can be performed at any position of the flexible flat cable 600. The flexible flat cable 600 has more grounding locations, which can effectively shorten the grounding return path, improve the grounding effect of the flexible flat cable 600, weaken the resonance of the insertion loss, and improve the signal quality of the flexible flat cable 600.

[0162] Fig.14a A schematic diagram of a grounding method for a flexible flat cable provided in an embodiment of the present application; Fig.14b A schematic diagram of another grounding method of a flexible flat cable provided in an embodiment of the present application. Fig.14a or Fig.14b As shown, as for the electrical contact between each grounding wire 61112 in the conductor layer 611 and the shielding film 620 (the shielding layer 621 therein), the present embodiment can adopt a method of opening a plurality of contact grooves 6121 on the hot melt adhesive layer 612 in the signal layer 610, each contact groove 6121 corresponds to each grounding wire 61112 one by one, and each contact groove 6121 extends to the exposed grounding wire 61112, so that the shielding film 620 (the shielding layer 621 therein) is in electrical contact with each grounding wire 61112 through the contact groove 6121.

[0163] For example, the contact grooves 6121 may be opened at the locations corresponding to the grounding wires 61112 on the hot melt adhesive layer 612 by laser engraving (laser) process. For example, laser engraving may be performed on the surface of the signal layer 610 before the signal layer 610 is connected to the shielding film 620 to form the contact grooves 6121 in the hot melt adhesive layer 612.

[0164] Among them, refer to Fig.14aAs shown, when the thickness of the hot melt adhesive layer 612 located on one side of the conductor layer 611 (in the thickness direction) is small, in other words, when the distance between the surface of the conductor layer 611 (the grounding wire 61112) and the inner surface of the shielding film 620 on the corresponding side (the surface of the shielding film 620 facing the signal layer 610) is small, that is, when the depth of the contact groove 6121 opened in the hot melt adhesive layer 612 is small, for example, when the depth of the contact groove 6121 is ≤30μm, the shielding film 620 itself can be relied on to fill the contact groove 6121, and the shielding film 620 is in direct contact with the grounding wire 61112 to achieve grounding of the shielding film 620 (the shielding layer 621 therein).

[0165] It can be understood that no matter the shielding film 620 relies on the adhesive layer 622 to adhere to the signal layer 610, or the shielding layer 621 in the shielding film 620 is directly sprayed and adsorbed on the surface of the signal layer 610, when the depth of the contact groove 6121 opened in the hot melt adhesive layer 612 is relatively small, the shielding film 620 can be filled into the contact groove 6121 under the action of external force or relying on its own material flow and deformation, and can be in direct contact with the grounding wire 61112.

[0166] Reference Fig.14b As shown, when the thickness of the hot melt adhesive layer 612 located on one side of the conductor layer 611 (in the thickness direction) is relatively large, in other words, when the distance between the surface of the conductor layer 611 (grounding wire 61112) and the inner surface of the shielding film 620 on the corresponding side (the surface of the shielding film 620 facing the signal layer 610) is relatively large, that is, when the depth of the contact groove 6121 opened in the hot melt adhesive layer 612 is relatively large, for example, when the depth of the contact groove 6121 is greater than 30 μm, due to the deep contact groove 6121, the shielding film 620 cannot completely fill the contact groove 6121 by relying on external force or its own material flow and deformation, and cannot reliably contact the grounding wire 61112.

[0167] At this time, before the shielding film 620 is connected to the signal layer 610, the contact groove 6121 opened on the hot melt adhesive layer 612 can be filled with the conductive medium 6122. In other words, the contact groove 6121 is filled with the conductive medium 6122. After the shielding film 620 is connected to the signal layer 610, one side of the conductive medium 6122 contacts the grounding wire 61112, and the other side of the conductive medium 6122 contacts the shielding film 620 (the shielding layer 621 therein), thereby achieving the grounding of the shielding film 620 (the shielding layer 621 therein).

[0168] The conductive medium 6122 may completely fill the contact groove 6121. Alternatively, the surface of the conductive medium 6122 may be slightly lower than the surface of the hot melt adhesive layer 612. In other words, the conductive medium 6122 does not completely fill the contact groove 6121, so as to reserve a certain deformation space for the connection between the shielding film 620 and the signal layer 610 (for example, the two are connected by a hot pressing process). Exemplarily, the conductive medium 6122 may be a conductive silver paste or a conductive copper paste.

[0169] Specifically, taking the shielding film 620 including the adhesive layer 622 as an example, if the adhesive layer 622 is the aforementioned conductive adhesive layer 6221, the shielding layer 621 can be electrically contacted with each grounding wire 61112 in the signal layer 610 through the conductive adhesive layer 6221. For example, the conductive adhesive layer 6221 is filled in the contact groove 6121 to directly contact the grounding wire 61112, or the conductive adhesive layer 6221 is electrically contacted with the grounding wire 61112 through the conductive medium 6122 filled in the contact groove 6121. If the adhesive layer 622 is the aforementioned non-conductive insulating adhesive layer, before the shielding film 620 is connected to the signal layer 610, a plurality of avoidance openings (not shown in the figure) can also be opened in the adhesive layer 622, each avoidance opening corresponds to each grounding wire 61112, or in other words, each avoidance opening corresponds to each contact groove 6121, and the shielding layer 621 is electrically contacted with the grounding wire 61112 through the avoidance opening and the contact groove 6121. For example, the shielding layer 621 is filled into the contact groove 6121 through the avoidance opening and directly contacts the grounding wire 61112, or the shielding layer 621 is in contact with the conductive medium 6122 filled in the contact groove 6121 through the avoidance opening (or the conductive medium 6122 filled in the contact groove 6121 enters the avoidance opening and contacts the shielding layer 621).

[0170] The following is an example in which the shielding film 620 of the present embodiment includes an adhesive layer 622, a shielding layer 621 and an insulating layer 623 stacked in sequence, specifically, the thickness of the adhesive layer 622 is 3 μm, the thickness of the shielding layer 621 is 0.25 μm, the thickness of the insulating layer 623 is 7 μm, and the total thickness of the shielding film 620 is 0.01 mm, and the test results of the signal quality of the flexible flat cable 600 of the present embodiment are described. Among them, the conventional flexible flat cable 600a mentioned above is used as a reference, and specifically, the total thickness of the insulating film 620a of the conventional flexible flat cable 600a is 0.2 mm as a reference.

[0171] In order to verify the signal quality of the flexible flat cable 600 of this embodiment, the thinning of the shielding film 620 in this embodiment affects the insertion loss of the characteristic impedance of the signal layer 610. Considering these two aspects, the characteristic impedance and insertion loss of the flexible flat cable 600 of this embodiment and the conventional flexible flat cable 600a were simulated and tested respectively.

[0172] Fig.15a The simulation test results of the characteristic impedance of a conventional flexible flat cable; Fig.15b The simulation test result of the characteristic impedance of the flexible flat cable of the embodiment of the present application; Fig.15c This is a comparison chart of simulation test results of characteristic impedances of the flexible flat cable according to the embodiment of the present application and a conventional flexible flat cable.

[0173] Reference Fig.15a As shown, the characteristic impedance value of the conventional flexible flat cable 600a is 45.4Ω; Fig.15b As shown, the characteristic impedance value of the improved flexible flat cable 600 in this embodiment is 42.6Ω; Fig.15c As shown, the characteristic impedance value of the flexible flat cable 600 of the embodiment of the present application is equivalent to that of the conventional flexible flat cable 600a. The characteristic impedance value of the flexible flat cable 600 of the embodiment of the present application can reach 42.6Ω, which meets the requirements of various current application scenarios.

[0174] Fig.16a The simulation test results of the insertion loss of a conventional flexible flat cable are shown below; Fig.16b The simulation test result of the insertion loss of the flexible flat cable of the embodiment of the present application; Fig.16c This is a comparison chart of simulation test results of insertion loss of the flexible flat cable according to the embodiment of the present application and a conventional flexible flat cable.

[0175] Reference Fig.16a As shown, the insertion loss value of the conventional flexible flat cable 600a is -1.9dB (5GHz); Fig.16b As shown, the insertion loss value of the improved flexible flat cable 600 in this embodiment is -2.2dB (5GHz); Fig.16c As shown, the insertion loss value of the flexible flat cable 600 of the embodiment of the present application is equivalent to that of the conventional flexible flat cable 600a. The insertion loss value of the flexible flat cable 600 of the present embodiment is increased by 0.27dB compared with the insertion loss value of the conventional flexible flat cable 600a, which meets the requirements of various current application scenarios.

[0176] In addition, this embodiment also compares the resonance of the insertion loss of the flexible flat cable 600 with a long link (longer length), referring to Fig.17As shown in the figure, the insertion loss index of the flexible flat cable 600 of this embodiment is compared with the insertion loss index of the conventional flexible flat cable 600a, taking the length of the flexible flat cable of 160mm as an example. As shown in the figure, the wave curve below is the insertion loss index of the conventional flexible flat cable 600a, and the curve of the insertion loss value has large vibration fluctuations. In the whole frequency band, the conventional flexible flat cable 600a has obvious resonance; the smooth curve above is the insertion loss index of the improved flexible flat cable 600 of this embodiment, and the curve of the insertion loss value is smooth. In the whole frequency band, the flexible flat cable 600 of this embodiment has almost no resonance (no oscillation point), and the signal quality is significantly improved.

[0177] This embodiment further provides a manufacturing process of a flexible flat cable 600 , which is used to manufacture the improved flexible flat cable 600 of the above-mentioned embodiment. The manufacturing process is described in detail below.

[0178] Fig.18 This is a flowchart of the steps of the manufacturing process provided in the embodiment of the present application. Fig.18 As shown, the manufacturing process for manufacturing the improved flexible flat cable 600 of this embodiment includes the following steps:

[0179] S100, forming a signal layer.

[0180] When manufacturing the improved flexible flat cable 600 of this embodiment, first, the signal layer 610 is manufactured. As mentioned above, the signal layer 610 includes a conductor layer 611 and a hot melt adhesive layer 612 wrapped around the outer periphery of the conductor layer 611, and the conductor layer 611 includes a plurality of wires 6111, and the plurality of wires 6111 include a plurality of signal wires 61111 and a plurality of ground wires 61112. In this regard, when manufacturing the signal layer 610, the plurality of wires 6111 can be shaped (including shape and position) first, including shaping each signal wire 61111 and each ground wire 61112 to form the conductor layer 611; then, the hot melt adhesive layer 612 is wrapped around the outer periphery of the conductor layer 611 to form the signal layer 610.

[0181] For example, a portion of the hot melt adhesive layer 612 may be provided first, and each conductor 6111 may be adhered to the portion of the hot melt adhesive layer 612 . Thereafter, another portion of the hot melt adhesive layer 612 may be adhered accordingly to form a complete hot melt adhesive layer 612 wrapped around the outer periphery of the conductor layer 611 .

[0182] It should be noted that before attaching the shielding film 620 to the signal layer 610, it is necessary to first form a plurality of contact grooves 6121 on the hot melt adhesive layer 612 of the signal layer 610, for example, by laser engraving, a plurality of contact grooves 6121 are opened on the signal layer 610, so that each contact groove 6121 corresponds to each grounding wire 61112 in the conductor layer 611, and the contact groove 6121 extends to expose the grounding wire 61112. After attaching the shielding film 620 to the surface of the hot melt adhesive layer 612, the shielding film 620 can be in electrical contact with each grounding wire 61112 through the contact groove 6121.

[0183] Among them, when the groove depth of the contact groove 6121 is small, the subsequent shielding film 620 can be directly attached; when the groove depth of the contact groove 6121 is large, the conductive medium 6122 can be filled in the contact groove 6121 first, for example, the conductive medium 6122 is deposited or sprayed in the contact groove 6121, and then the shielding film 620 is attached.

[0184] In addition, after the signal layer 610 is formed and before the shielding film 620 is connected to the signal layer 610, the electrical properties of the signal layer 610 may be tested, for example, the circuit on / off, voltage, current, etc. of the signal layer 610 may be tested. If the electrical properties of the signal layer 610 meet the requirements, the subsequent shielding film 620 attachment step is performed; if the electrical properties of the signal layer 610 do not meet the requirements, the signal layer 610 is scrapped or reworked.

[0185] S200, attaching shielding films to both side surfaces of the signal layer in the thickness direction to form a flexible flat cable.

[0186] After the signal layer 610 is manufactured, the shielding film 620 is attached to both side surfaces of the signal layer 610 in the thickness direction to form the flexible flat cable 600 .

[0187] It should be noted that when the shielding film 620 includes an adhesive layer 622, the shielding film 620 can be first produced separately, and then the shielding film 620 can be bonded as a whole to the signal layer 610; when the shielding film 620 does not include an adhesive layer 622 and the shielding layer 621 is directly attached to the signal layer 610, the various structural layers of the shielding film 620 can be formed on the signal layer 610 in sequence, for example, the shielding layer 621 can be sprayed or (vacuum) adsorbed on the signal layer 610, and if the shielding film 620 also has an insulating layer 623, the insulating layer 623 can be sprayed or bonded to the shielding layer 621.

[0188] The following uses the example that the shielding film 620 includes an adhesive layer 622 , a shielding layer 621 , and an insulating layer 623 that are sequentially arranged to illustrate the subsequent steps.

[0189] Fig.19This is a flowchart of the steps for making a shielding film provided in an embodiment of the present application. Fig.19 As shown, specifically, the adhesive layer 622 can be first disposed on the carrier film as described above, and the adhesive layer 622 and the carrier film can be laid flat on a pressing carrier. After that, the shielding layer 621 is attached to the adhesive layer 622, and then the insulating layer 623 is attached to the shielding layer 621 to form the shielding film 620 as a whole.

[0190] Among them, taking the shielding layer 621 as a metal layer (such as a silver layer) as an example, when the shielding layer 621 is thicker, a complete shielding layer 621 can be provided, and the shielding layer 621 can be bonded to the adhesive layer 622 by hot pressing using the viscosity of the adhesive layer 622; when the shielding layer 621 is thinner, a spraying process can be used to spray metal slurry (such as silver slurry) on the adhesive layer 622 to a certain thickness to form the shielding layer 621.

[0191] The insulating layer 623 can be formed on the shielding layer 621 by spraying. For example, an insulating material (such as ink) can be sprayed on the shielding layer 621 to form the insulating layer 623 (such as an ink layer); or a very thin insulating film (such as a PET film, a PP film) can be provided and the insulating film can be adhered to the shielding layer 621 to form the insulating layer 623.

[0192] After the shielding film 620 is formed, the shielding film 620 is laminated to both sides of the signal layer 610 (in the thickness direction) by a hot pressing process to form the flexible flat cable 600. The pressing temperature is, for example, 180°C, the pressing pressure is, for example, 100 MPa, and the hot melt adhesive is cured after a period of time, for example, about 30 minutes.

[0193] After the flexible flat cable 600 is formed, there are steps such as automatically bending the flexible flat cable 600 and installing connectors at both ends thereof (the connectors are electrically connected to the gold fingers 601 at the ends of the flexible flat cable 600), and finally obtaining the finished product of the flexible flat cable 600.

[0194] After obtaining the finished product of the flexible flat cable 600, it is necessary to test the electrical performance of the flexible flat cable 600, for example, testing the circuit continuity, voltage, current, etc. of the flexible flat cable 600. If the electrical performance of the flexible flat cable 600 meets the requirements, the flexible flat cable 600 is subjected to a final inspection (such as appearance inspection, aging performance inspection), and is put into storage after passing the inspection; if the electrical performance of the flexible flat cable 600 does not meet the requirements, the flexible flat cable 600 is scrapped or reworked.

[0195] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0196] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

Claims

1. A flexible flat cable, characterized in that: It comprises a signal layer and a shielding film. The shielding film is attached to both side surfaces of the signal layer in the thickness direction. The thickness of the shielding film ranges from 0.5 μm to 12 μm.

2. The flexible flat cable according to claim 1, characterized in that: The signal layer comprises a conductor layer and a hot melt adhesive layer, the hot melt adhesive layer is wrapped around the outer periphery of the conductor layer, and the shielding film is attached to the surface of the hot melt adhesive layer; Wherein, the conductor layer includes a plurality of conductive wires, and the plurality of conductive wires include a plurality of signal wires and a plurality of ground wires, the ground wires are arranged at intervals along the plane direction of the conductor layer, and the ground wires are in electrical contact with the shielding film.

3. The flexible flat cable according to claim 2, characterized in that: The hot melt adhesive layer is provided with a plurality of contact grooves, each of which corresponds to each of the grounding wires one by one, and the contact grooves extend to expose the grounding wires, and the grounding wires are in electrical contact with the shielding film through the contact grooves.

4. The flexible flat cable according to claim 3, characterized in that: The shielding film fills the contact groove and contacts the ground line.

5. The flexible flat cable according to claim 3, characterized in that: The contact groove is filled with a conductive medium, and two sides of the conductive medium are respectively in contact with the grounding wire and the shielding film.

6. The flexible flat cable according to any one of claims 1 to 5, characterized in that: The shielding film comprises a shielding layer, and the thickness of the shielding layer is in the range of 0.15 μm-0.35 μm.

7. The flexible flat cable according to claim 6, characterized in that: The shielding film further comprises an adhesive layer, wherein the adhesive layer is attached to a side of the shielding layer facing the signal layer, and the adhesive layer is bonded and connected to the signal layer.

8. The flexible flat cable according to claim 7, characterized in that: The adhesive layer is a conductive adhesive layer, and the conductive adhesive layer is in electrical contact with each grounding line in the signal layer.

9. The flexible flat cable according to claim 7, characterized in that: The adhesive layer is an insulating adhesive layer, and a plurality of avoidance openings are provided in the adhesive layer, each of the avoidance openings corresponds to each grounding wire in the signal layer one by one, and the shielding layer is in electrical contact with the grounding wire through the avoidance openings.

10. The flexible flat cable according to claim 7, characterized in that: The thickness of the adhesive layer is in the range of 1.5 μm to 4.5 μm.

11. The flexible flat cable according to claim 6, characterized in that: The shielding layer is a conductive layer sprayed on the surface of the signal layer, or the shielding layer is a metal layer adsorbed on the surface of the signal layer.

12. The flexible flat cable according to claim 7 or 11, characterized in that: The shielding film further includes an insulating layer, wherein the insulating layer covers a side of the shielding layer away from the signal layer.

13. The flexible flat cable according to claim 12, characterized in that: The insulating layer is a sprayed layer sprayed on the surface of the shielding layer, or the insulating layer is an insulating film adhered to the surface of the shielding layer.

14. The flexible flat cable according to claim 12, characterized in that: The thickness of the insulating layer is in the range of 4.5 μm to 9.5 μm.

15. The flexible flat cable according to claim 6, characterized in that The shielding layer is a liquid metal layer.

16. A process for manufacturing a flexible flat cable, used for manufacturing the flexible flat cable according to any one of claims 1 to 15, characterized in that: The manufacturing process comprises: Producing and forming a signal layer; Shielding films are attached to both side surfaces of the signal layer in a thickness direction to form a flexible flat cable.

17. The manufacturing process of the flexible flat cable according to claim 16, characterized in that: Attaching the shielding film to the surface of the signal layer comprises: Manufacturing and forming a shielding film; The shielding film is attached to the surface of the signal layer.

18. The manufacturing process of the flexible flat cable according to claim 17, characterized in that: The shielding film comprises a shielding layer and an adhesive layer attached to the surface of the shielding layer, and the shielding film is formed by: disposing the adhesive layer on a carrier film; The shielding layer is attached to the adhesive layer.

19. The manufacturing process of the flexible flat cable according to claim 18, characterized in that: Attaching the shielding layer to the adhesive layer comprises: placing the shielding layer on the adhesive layer in a hot-melt state to attach the shielding layer to the adhesive layer; or, A shielding material is sprayed on the adhesive layer to form a shielding layer on the adhesive layer.

20. The manufacturing process of the flexible flat cable according to claim 18, characterized in that: The shielding film further comprises an insulating layer, and after the shielding layer is attached to the adhesive layer, the shielding film further comprises: The insulating layer is attached to the shielding layer.

21. The manufacturing process of the flexible flat cable according to claim 20, characterized in that: Attaching the insulating layer to the shielding layer comprises: Spraying insulating material on the shielding layer to form an insulating layer; or, An insulating film is attached to the shielding layer to form the insulating layer.

22. The manufacturing process of the flexible flat cable according to any one of claims 16 to 21, characterized in that: The signal layer includes a conductor layer and a hot melt adhesive layer, and the conductor layer includes a plurality of wires. The signal layer is formed by: shaping the plurality of conductive wires to form a conductor layer; A hot melt adhesive layer is wrapped around the outer periphery of the conductor layer to form the signal layer.

23. The manufacturing process of the flexible flat cable according to claim 22, characterized in that: The plurality of wires include a plurality of signal wires and a plurality of ground wires, and the ground wires are arranged at intervals along the plane direction of the conductor layer; After the signal layer is formed, the process includes: Forming a plurality of contact grooves on the hot melt adhesive layer, so that each contact groove corresponds to each grounding wire one by one, and the contact grooves extend to expose the grounding wires; The shielding film is attached to the surface of the hot melt adhesive layer so that the shielding film is in electrical contact with the grounding wire through the contact groove.

24. The manufacturing process of the flexible flat cable according to any one of claims 16 to 21, characterized in that: After the signal layer is formed and before the shielding film is attached to the surface of the signal layer, the method further includes: Conducting an electrical performance test on the signal layer; wherein, If the electrical performance of the signal layer meets the requirements, the shielding film is attached; if the electrical performance of the signal layer does not meet the requirements, the signal layer is scrapped or reworked.

25. The manufacturing process of the flexible flat cable according to any one of claims 16 to 21, characterized in that: After forming the flexible flat cable, the method further comprises: Conducting an electrical performance test on the flexible flat cable; wherein, If the electrical performance of the flexible flat cable meets the requirements, the flexible flat cable is subjected to a final inspection; if the electrical performance of the flexible flat cable does not meet the requirements, the flexible flat cable is scrapped or reworked.

26. An electronic device, characterized in that: The invention comprises a housing assembly and the flexible flat cable according to any one of claims 1 to 15, wherein the flexible flat cable is located in the housing assembly.

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