High-frequency flexible flat cable (FFC)

Abstract

The utility model relates to the technical field of flexible flat cable manufacturing, in particular to a high-frequency flexible flat cable (FFC). The short-state shielding body and the long-state shielding body cooperate to form an electromagnetic wave isolation barrier on the periphery of the conduction transmission unit. The conduction transmission unit is composed of a power transmission wire, a signal transmission wire and a shielding wire which are arranged in parallel. The plurality of signal transmission wires are arranged in a concentrated manner, the at least one shielding wire is arranged in the signal transmission wires, and the power transmission wires are arranged on two side areas of the signal transmission wires. The shielding wire is grounded and is electrically connected with the short-state shielding body and the long-state shielding body at the same time. Thus, on one hand, the signal crosstalk phenomenon is effectively eliminated, it is ensured that high-frequency signals always keep good stability in the transmission process, and loss and distortion in the signal transmission process are greatly reduced; and on the other hand, due to the high-conductivity design of the shielding wire, the interference current can flow to the grounded short-state shielding body and the grounded long-state shielding body in real time in a low-resistance-consumption manner, and the electromagnetic shielding effect can be further enhanced.

Description

TECHNICAL FIELD

[0001] The utility model relates to soft cable manufacturing technical field especially a kind of high-frequency FFC cable. BACKGROUND

[0002] FFC cable is also called Flexible Flat Cable, which is a key element for data transmission between components and mainboard, PCB and small-sized electrical equipment. Its performance directly affects the running stability and efficiency of the whole system.

[0003] In terms of current industry status, conventional FFC cable is mainly composed of conductor layer, long-state insulating layer and short-state insulating layer. The conductor layer is composed of multiple parallel arranged signal conductors and power conductors. The long-state insulating layer and the short-state insulating layer are both grounded and cooperatively wrap the conductor layer to make the FFC cable have certain anti-electromagnetic ability. However, the conventional FFC cable has sharp increase in attenuation under high-frequency condition, which cannot meet the current demand for high-speed and stable signal transmission, and seriously restricts the improvement of data processing and transmission rate of electronic equipment. In addition, the conventional FFC cable has serious deficiency in electromagnetic shielding, is easily disturbed by external electromagnetic waves and is difficult to effectively guarantee the stability of high-frequency signal transmission. In summary, it is urgent to develop a FFC cable with excellent electromagnetic shielding performance, reasonable wire layout and stable high-frequency signal transmission. SUMMARY

[0004] Therefore, the development and design group collects relevant data, evaluates and considers from multiple aspects, and finally leads to the emergence of the high-frequency FFC cable through continuous experiments and modifications of the personnel of the development and design group.

[0005] In order to solve the above technical problems, the utility model relates to a kind of high-frequency FFC cable, including short-state shielding body, conducting transmission unit and long-state shielding body. The short-state shielding body and the long-state shielding body are both grounded and cooperatively form electromagnetic wave isolation barrier around the conducting transmission unit. The conducting transmission unit is composed of parallel arranged power transmission wire, signal transmission wire and shielding wire. Multiple signal transmission wires are arranged in concentration, and at least one shielding wire is mixed in them to form embedded shielding structure, and power transmission wire is arranged in the region on both sides. Shielding wire is electrically connected to short-state shielding body and long-state shielding body. The electrical conductivity of power transmission wire, signal transmission wire and shielding wire is σ1, σ2 and σ3 respectively, and σ3>σ1, σ3>σ2.

[0006] As a further improvement of the disclosed technical scheme of the utility model, the power transmission wire and the signal transmission wire are both plated tin flat copper wire. The shielding wire is plated silver flat copper wire.

[0007] As a preferred scheme, the short-state shielding body is composed of the upper aluminum-plastic composite tape, the upper dielectric layer and the upper hot melt adhesive layer in sequence.

[0008] As a further improvement of the disclosed technical scheme, the high-frequency FFC flat cable further comprises an end auxiliary reinforcing body.

[0009] As a further improvement of the disclosed technical scheme, the end auxiliary reinforcing body is composed of a plurality of non-metallic gaskets.

[0010] As another preferred scheme, the short-state shielding body is composed of the upper aluminum foil PET composite, the upper conductive hot melt adhesive layer and the upper high-frequency resistant functional layer in sequence.

[0011] As a further improvement of the disclosed technical scheme, the high-frequency FFC flat cable further comprises a reinforcing plate, a non-metallic reinforcing body and a double conductive aluminum foil.

[0012] As a further improvement of the disclosed technical scheme, the upper aluminum foil PET composite and the lower aluminum foil PET composite have the same design structure and are composed of a PET layer, a composite adhesive layer and an aluminum foil layer in sequence.

[0013] As a further improvement of the disclosed technical scheme, the upper high-frequency resistant functional layer and the lower high-frequency resistant functional layer have the same design structure and are composed of a polyimide layer, an adhesive layer, a PO substrate layer and a low dielectric constant adhesive layer in sequence.

[0014] As a further improvement of the disclosed technical scheme, the low dielectric constant adhesive layer is preferably an acrylate hot melt adhesive, a polyester hot melt adhesive, a polyurethane hot melt adhesive or a fluoropolymer.

[0015] In practical application, the high-frequency FFC flat cable disclosed by the utility model can achieve the following beneficial technical effects, specifically:

[0016] 1) Multiple signal transmission wires are arranged in a concentrated manner, and shielding wires are mixed therein to form an embedded shielding structure. In addition, the shielding wires are connected to ground, and are electrically connected to the short-state shielding body and the long-state shielding body at the same time, so that a complete and efficient electromagnetic wave isolation barrier can be constructed around the transmission unit. In this way, the signal crosstalk phenomenon between adjacent signal transmission wires can be effectively eliminated, the stability of high-frequency signals during transmission can be ensured, and the loss and distortion during signal transmission can be greatly reduced.

[0017] 2) Compared with the power transmission wires and the signal transmission wires, the shielding wires have higher conductivity, so that the interference current can be immediately and low-resistance guided to the short-state shielding body and the long-state shielding body connected to ground, thereby enhancing the electromagnetic shielding effect of the high-frequency FFC flat cable.

[0018] 3) The power transmission wires generate a large current during operation, and are arranged separately from the signal transmission wires, so that the interference caused by the large current during power transmission on the high-frequency signal transmission process can be effectively weakened, and the high-frequency signals can be transmitted with high quality. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 is a perspective view of the first embodiment of the high-frequency FFC flat cable disclosed in the present utility model.

[0021] Figure 2 is Figure 1 a partial enlarged view of I.

[0022] Figure 3 is Figure 1 a top view of I.

[0023] Figure 4 is a longitudinal sectional view of the first embodiment of the high-frequency FFC flat cable disclosed in the present utility model.

[0024] Figure 5 is a longitudinal sectional view of the second embodiment of the high-frequency FFC flat cable disclosed in the present utility model.

[0025] 1 - short state shielding body; 11 - upper aluminum plastic composite tape; 12 - upper dielectric layer; 13 - upper hot melt adhesive layer; 14 - upper aluminum foil PET composite; 15 - upper conductive hot melt adhesive layer; 16 - upper high-frequency resistant functional layer; 2 - on-off transmission unit; 21 - power transmission wire aggregation area; 22 - signal transmission wire aggregation area; 23 - shielding wire aggregation area; 3 - long state shielding body; 31 - lower aluminum plastic composite tape; 311 - aluminum foil exposed area; 32 - lower dielectric layer; 33 - lower hot melt adhesive layer; 34 - lower aluminum foil PET composite; 35 - lower conductive hot melt adhesive layer; 36 - lower high-frequency resistant functional layer; 4 - end auxiliary reinforcing body; 41 - non-metallic gasket; 5 - reinforcing plate; 6 - non-metallic reinforcing body; 7 - double aluminum foil. DETAILED DESCRIPTION

[0026] In the description of the present application, it should be understood that the terms "left", "right", "up", "down", "front", "back", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application.

[0027] The content disclosed by the present application will be further described in detail below in combination with specific embodiments, Figure 1 , Figure 2 , Figure 4 The structure diagram of the first embodiment of the high-frequency FFC flat cable disclosed in the present application is shown, which can be known that it mainly consists of a short state shielding body 1, an on-off transmission unit 2, a long state shielding body 3 and an end auxiliary reinforcing body 4, wherein the short state shielding body 1 and the long state shielding body 3 are both grounded, arranged on the upper and lower sides of the on-off transmission unit 2 respectively, and cooperated to form an electromagnetic wave isolation barrier around the on-off transmission unit 2. The end auxiliary reinforcing body 4 is arranged at both ends of the high-frequency FFC flat cable, and is interposed between the long state shielding body 3 and the on-off transmission unit 2. The end auxiliary reinforcing body 4 is composed of at least two non-metallic gaskets 41 stacked and combined. The end auxiliary reinforcing body 4 is used to increase the hardness and strength of the end of the high-frequency FFC flat cable, so that it is easier to be inserted into the connector or other interface, and prevent the end of the high-frequency FFC flat cable from bending, deforming or damaging during the plugging process.

[0028] As Figure 3As shown in the figure, according to the functional difference, the conducting transmission unit 2 is divided into a power transmission wire gathering area 21, a signal transmission wire gathering area 22 and a shielding wire gathering area 23. In the power transmission wire gathering area 21, a plurality of parallel arranged power transmission wires are arranged. In the signal transmission wire gathering area 22, a plurality of parallel arranged signal transmission wires are arranged. In the shielding wire gathering area 23, at least one shielding wire is arranged, and it is electrically connected to the short state shielding body 1 and the long state shielding body 3. The shielding wire is mixed in the signal transmission wire gathering area 22 to form an embedded shielding structure.

[0029] In practical application, the high frequency FFC flat cable disclosed by the utility model has at least the following two technical effects, specifically:

[0030] 1) A plurality of signal transmission wires are arranged in a concentrated manner, and a shielding wire is mixed therein to form an embedded shielding structure. In addition, the shielding wire is grounded, and it is electrically connected to the short state shielding body 1 and the long state shielding body 3, so that a complete and efficient electromagnetic wave isolation barrier can be built around the conducting transmission unit 2. In this way, the signal crosstalk phenomenon between adjacent signal transmission wires is effectively eliminated, the stability of high frequency signals during transmission is ensured, and the loss and distortion during signal transmission can be greatly reduced.

[0031] 2) The power transmission wire generates a large current during work, and is arranged separately from the signal transmission wire, so that the interference of the large current generated during power transmission on the high frequency signal transmission process can be effectively weakened, and the high frequency signal can be transmitted with high quality.

[0032] Here, it should be noted that compared with the power transmission wire and the signal transmission wire, the shielding wire has higher electrical conductivity, that is, the electrical conductivities of the power transmission wire, the signal transmission wire and the shielding wire are σ1, σ2 and σ3 respectively, and σ3>σ1 and σ3>σ2. In practical application, the interference current can be immediately and low-resistance guided to the short state shielding body 1 and the long state shielding body 3, thereby enhancing the electromagnetic shielding effect of the high frequency FFC flat cable.

[0033] As a preferred design, the power transmission wire and the signal transmission wire are preferably tinned flat copper wires. The shielding wire is preferably a silver-plated flat copper wire. In this way, the shielding wire has higher electrical conductivity, which is conducive to the flow direction guidance of the interference current. And it can effectively reduce the transmission loss, reduce signal distortion and attenuation, and ensure the reliability of the shielding effect.

[0034] Furthermore, the shielding wire is mixed in the signal transmission wire gathering area 22 to form an embedded shielding structure. Figure 4As can be clearly seen from the drawings, the short-state shielding body 1 is composed of the upper aluminum-plastic composite tape 11, the upper dielectric layer 12 and the upper hot melt adhesive layer 13 in sequence towards the on-off transmission unit 2, and the long-state shielding body 3 is composed of the lower aluminum-plastic composite tape 31, the lower dielectric layer 32 and the lower hot melt adhesive layer 33 in sequence. In order to realize the grounding design, the end of the lower aluminum-plastic composite tape 31 is subjected to plastic removal treatment to form an aluminum foil exposed area 311 in communication with the grounding PIN of the electrical connector. In practical application, the upper aluminum-plastic composite tape 11 and the lower aluminum-plastic composite tape 31 can shield high-frequency electromagnetic waves, thereby effectively eliminating the signal interference of external high-frequency electromagnetic waves on the on-off transmission unit 2 and ensuring the stability of data transmission. The upper dielectric layer 12 and the lower dielectric layer 32 are non-conductive film materials to form electrical isolation between the on-off transmission unit 2 and the short-state shielding body 1 and the long-state shielding body 3.

[0035] Figure 5 The structure schematic diagram of the second embodiment of the high-frequency FFC flat cable disclosed in the utility model is shown, and it can be known that the second embodiment also comprises the short-state shielding body 1, the on-off transmission unit 2 and the long-state shielding body 3. Compared with the first embodiment, the difference lies in that the short-state shielding body 1 is composed of the upper aluminum foil PET composite 14, the upper conductive hot melt adhesive layer 15 and the upper high-frequency resistant functional layer 16 in sequence. The long-state shielding body 3 is composed of the lower aluminum foil PET composite 34, the lower conductive hot melt adhesive layer 35 and the lower high-frequency resistant functional layer 36 in sequence. The upper aluminum foil PET composite 14 and the lower aluminum foil PET composite 34 have the same design structure and are composed of a PET layer, a composite adhesive layer and an aluminum foil layer in sequence. The lower aluminum foil PET composite 34 is in communication with the grounding PIN of the electrical connector, so that induced charges can be introduced into the ground in time to avoid the accumulation of charges and effectively reduce the strength of electromagnetic interference and improve the anti-interference ability of the FFC flat cable.

[0036] In practical application, the upper aluminum foil PET composite 14 and the lower aluminum foil PET composite 34 both have excellent conductivity and shielding performance, which is beneficial to reducing electromagnetic interference. PET serves as a base material to provide support and protection for the aluminum foil. The upper high-frequency resistant functional layer 16 and the lower high-frequency resistant functional layer 36 can effectively prevent signal leakage and reduce the generation of electromagnetic interference, and can also resist the interference of external high-frequency electromagnetic waves, thereby ensuring the stability and reliability of the FFC flat cable in a high-frequency working environment.

[0037] It is needed to emphasize here that the upper high-frequency resistant functional layer 16 and the lower high-frequency resistant functional layer 36 have the same design structure, and are sequentially stacked by a polyimide layer, an adhesive layer, a PO substrate layer and a low dielectric constant adhesive layer. The low dielectric constant adhesive layer is preferably an acrylate hot melt adhesive, a polyester hot melt adhesive, a polyurethane hot melt adhesive or a fluoropolymer. In this way, the upper high-frequency resistant functional layer 16 and the lower high-frequency resistant functional layer 36 both have the characteristics of excellent low dielectric constant and low dielectric loss, can effectively prevent signal leakage and electromagnetic interference, and can ensure the integrity and stability of the signal during high-frequency signal transmission, reduce signal delay, distortion, attenuation and distortion.

[0038] Furthermore, as shown in Figure 5 The high-frequency FFC flat cable is also provided with a reinforcing plate 5, a non-metallic reinforcing body 6 and a double-conductive aluminum foil 7. The reinforcing plate 5 is connected to the end of the lower aluminum foil PET composite 34, and the non-metallic reinforcing body 6 is interposed between the reinforcing plate 5 and the conductive transmission unit 2. The double-conductive aluminum foil 7 is conductive to the lower aluminum foil PET composite 34 and the ground PIN of the electrical connector, and is attached to the reinforcing plate 5 and partially covers the lower aluminum foil PET composite 34. In this way, on the one hand, the reinforcing plate 5 and the non-metallic reinforcing body 6 cooperate to enhance the rigidity and strength of the end of the FFC flat cable, so that it is not easy to deform, break or be damaged when connected to other components or subjected to external force; on the other hand, thanks to the application of the double-conductive aluminum foil 7 and the electrical connection mode, electromagnetic interference in the high-frequency FFC flat cable can be effectively guided to the ground to form a good grounding path, so as to better block the interference of external electromagnetic waves on the internal signals of the flat cable.

[0039] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-frequency FFC flat cable, characterized by, The short-state shielding body and the long-state shielding body are both grounded and cooperatively form an electromagnetic wave isolation barrier around the conductive transmission unit. The conductive transmission unit is composed of parallelly arranged power transmission wires, signal transmission wires and shielding wires. The shielding wires are electrically connected to the short-state shielding body and the long-state shielding body.

2. The high-frequency FFC cable according to claim 1, wherein The power transmission wires and the signal transmission wires are both flat copper wires plated with tin, and the shielding wires are flat copper wires plated with silver.

3. The high-frequency FFC cable according to any one of claims 1 to 2, characterized by, The short-state shielding body is composed of an upper aluminum-plastic composite tape, an upper dielectric layer and an upper hot melt adhesive layer in sequence, and the long-state shielding body is composed of a lower aluminum-plastic composite tape, a lower dielectric layer and a lower hot melt adhesive layer in sequence.

4. The high-frequency FFC cable according to claim 3, wherein The end portion of the lower aluminum-plastic composite tape is subjected to plastic removal treatment to form an aluminum foil exposed area in conductive connection with a ground pin of an electrical connector.

5. The high-frequency FFC cable according to claim 4, wherein The end portion auxiliary reinforcing body is arranged at both ends of the high-frequency FFC flat cable and is interposed between the long-state shielding body and the conductive transmission unit.

6. The high-frequency FFC cable according to any one of claims 1 to 2, wherein The end portion auxiliary reinforcing body is composed of a plurality of non-metallic gaskets.

7. The high-frequency FFC cable according to claim 6, wherein The short-state shielding body is composed of an upper aluminum foil PET composite, an upper conductive hot melt adhesive layer and an upper high-frequency resistant functional layer in sequence, and the long-state shielding body is composed of a lower aluminum foil PET composite, a lower conductive hot melt adhesive layer and a lower high-frequency resistant functional layer in sequence.

8. The high-frequency FFC cable of claim 6, wherein, The lower aluminum foil PET composite is in conductive connection with a ground pin of an electrical connector.

9. The high-frequency FFC cable of claim 6, wherein, The upper aluminum foil PET composite and the lower aluminum foil PET composite have the same design structure and are both composed of a PET layer, a composite adhesive layer and an aluminum foil layer in sequence.

10. The high-frequency FFC cable according to claim 9, wherein The upper high-frequency resistant functional layer and the lower high-frequency resistant functional layer have the same design structure and are both composed of a polyimide layer, an adhesive layer, a PO substrate layer and a low dielectric constant adhesive layer in sequence. The low dielectric constant adhesive layer is an acrylate hot melt adhesive, a polyester hot melt adhesive, a polyurethane hot melt adhesive or a fluoropolymer.

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