CN107799211A - Flexible flat cable structure and flexible flat cable electric connector fixing structure - Google Patents

Abstract

A flexible flat cable structure comprises a plurality of transmission line groups and a second insulating outer sleeve. A plurality of the transmission line groups are arranged in parallel, and a gap is maintained between each transmission line group and the adjacent transmission line group. Each transmission line group comprises at least one signal line, a first shielding layer, a first grounding conductor and a second shielding layer. Each signal line comprises a signal conductor and a first insulating outer sleeve. The signal conductor is used to transmit data signals or power. The first insulating jacket covers the signal conductor. The first shielding layer surrounds the signal lines and contacts the first insulating jacket of each signal line. The first grounding conductor is positioned at one side of the signal wire and contacts the first shielding layer for transmitting grounding voltage. The second shielding layer surrounds and contacts the first ground conductor and the first shielding layer. The second insulating outer sleeve coats a plurality of second shielding layers of the transmission line group.

Description

Flexible flat cable structure and flexible flat cable electrical connector fixing structure

【Technical field】

The invention relates to a flexible flat cable structure, in particular to a flexible flat cable structure for reducing electromagnetic interference.

【Background technique】

Flexible Flat Cable (Flex Flat Cable, FFC) is a new type of data cable. It is made of insulating material and extremely thin tinned flat copper wire, which is pressed by automatic equipment. Due to the characteristics of neat arrangement of wire cores, large transmission capacity, flat structure, small size, convenient disassembly, and flexibility, it can be easily and flexibly applied to various electronic products as data transmission cables. Flexible flat flat cables are especially suitable for various high-frequency bending applications, such as the connection of moving parts. In terms of connection, it can not only be plugged in with a connector, but also directly soldered to a printed circuit board.

The size of electronic products tends to be compact, so the size of cables used in electronic products must also be reduced accordingly. In addition, the data transmission speed of electronic products is moving towards high speed, and the requirements for the high-speed signal transmission quality of transmission lines are also getting higher and higher. In order to improve the quality of transmission lines, it is necessary to reduce the interference between signal lines and improve the electromagnetic interference (Electromagnetic Disturbance) generated during signal transmission. , EMI) problem. There is no metal shield between the signal lines of the traditional flat cable, which will interfere with adjacent signal lines during high-speed signal transmission and affect the quality of signal transmission. Traditional flat cables can reduce interference to adjacent signal lines during high-speed signal transmission by coating the outside of the signal lines with metal foil. However, the metal shielding of all the signal lines of the traditional flat cable is only covered with a single layer of metal foil, and the metal foil only contacts with a single ground conductor. However, the traditional flat cable is prone to unstable contact between the metal foil and a single ground conductor due to bending.

【Content of invention】

In view of this, it is necessary to provide a flexible flat cable structure and a flexible flat cable electrical connector fixing structure to solve the technical problem of unstable contact between the metal foil and a single ground conductor due to bending of the traditional flat cable.

The embodiment of the invention discloses a flexible flat cable structure, which includes several transmission line groups and a second insulating jacket. Several transmission line groups are arranged parallel to each other, and a distance is maintained between each transmission line group and the adjacent transmission line group. Each transmission line group includes at least one signal line, a first shielding layer, a first ground conductor and a second shielding layer. Each signal line includes a signal conductor and a first insulating jacket. The signal conductor is used to transmit data signals or power. The first insulating jacket covers the signal conductor. The first shielding layer surrounds the signal wires and contacts the first insulating jacket of each signal wire. The first ground conductor is located at one side of the signal line and contacts the first shielding layer for transmitting ground voltage. The second shielding layer surrounds and contacts the first ground conductor and the first shielding layer. The second insulating jacket covers the second shielding layers of the transmission line sets.

According to an embodiment of the present invention, in some transmission line groups, the first insulating jackets of at least two adjacent signal lines of the signal lines are in contact with each other.

According to an embodiment of the present invention, there is a buffer space between at least two of the signal lines of the partial transmission line group and the first shielding layer.

According to an embodiment of the present invention, part of the transmission line group further includes a second ground conductor, the first ground conductor and the second ground conductor are respectively located on both sides of the two signal lines and contact the first shielding layer for transmission ground voltage.

According to an embodiment of the present invention, there is a buffer space between the second ground conductor, the first shielding layer and the second shielding layer of some transmission line groups.

According to an embodiment of the present invention, there is a buffer space between the first ground conductor, the first shielding layer and the second shielding layer of each transmission line group.

According to an embodiment of the present invention, the first shielding layer includes a first conductive layer and an isolation layer. The first conductive layer contacts the second shielding layer. The isolation layer covers the first insulating jacket.

According to an embodiment of the present invention, the second shielding layer includes a second conductive layer and a third conductive layer. The second conductive layer contacts the first ground conductor and the first conductive layer. The third conductive layer contacts the second insulating jacket.

According to an embodiment of the present invention, the first insulating jacket and the second insulating jacket are made of polyethylene (polyethylene, PE), polyvinyl chloride (polyvinyl chloride, PVC), thermoplastic elastomer (ThermoplasticElastomer, TPE), thermoplastic polyurethane ( Thermoplastic Polyurethane, TPU), thermoplastic rubber (thermoplastic rubber, TPR), thermoplastic polyolefin (Thermoplastic Polyolefin, TPO), polyurethane (Polyurethane, PUR), polypropylene (Polypropylene, PP), polyolefin (Polyolefins, PO), PVDF ( PolyVinyliDene Fluoride), ethylene-chlorotrifluoroethylene copolymer (Ethylene-chlorotrifluoroethylene copolymer, ECTFE), ethylene-tetrafluoroethylene copolymer (ethylene-tetra-fluoro-ethylene, ETFE), Teflon polyperfluoroethylene propylene resin ( Teflon Fluorinated ethylenepropylene, Teflon FEP), polytetrafluoroethylene (Polytetrafluoroethene, PTFE), Teflon (Teflon) or nylon (Nylon).

The embodiment of the invention further discloses a flexible flat cable electrical connector fixing structure, which includes: an electrical connector and a flexible flat cable structure. The electrical connector includes a base, a circuit board, several terminals and a shell. The spacer is assembled on the base, and the spacer has several receiving grooves. The circuit board has several conductive parts and several connecting parts, and the several conductive parts are electrically connected to corresponding connecting parts. One ends of the several terminals pass through the corresponding receiving grooves and are connected to the several connecting parts. The shell is assembled on the base. The flexible flat cable structure includes the aforementioned flexible flat cable structure.

The present invention has the following beneficial effects: Compared with the prior art, the flexible flat cable structure and the flexible flat cable electrical connector fixing structure of the embodiment of the present invention divide all signal lines into several transmission line groups, and each transmission line group contains A first shield, a second shield and a ground conductor. The first shielding layer and the second shielding layer have the ability to reflect and absorb electromagnetic waves. The ground conductor is disposed between the first shielding layer and the second shielding layer, so that both the first shielding layer and the second shielding layer can come into contact with the grounding conductor, so that the grounding conductor and the first shielding layer The double-sided contact with the second shielding layer will make the shielding grounding structure of the flexible flat cable relatively stable. The signal wires of each transmission line group wrap the first shielding layer and the second shielding layer respectively so that the flexible flat cable structure has better EMI resistance than the traditional flat cable, so the flexible flat cable structure of the present invention It can improve the EMI problem generated by traditional flat cables during signal transmission.

In order to make the above content of the present invention more obvious and understandable, the following preferred embodiments are specifically cited below, and in conjunction with the accompanying drawings, the detailed description is as follows:

【Description of drawings】

Fig. 1 is an exploded view of the fixing structure of the flexible flat cable electrical connector of the present invention.

FIG. 2 and FIG. 3 are composite views of different viewing angles of the fixing structure of the flexible flat cable electrical connector in FIG. 1 .

Fig. 4 is a top view of the fixing structure of the flexible flat cable electrical connector in Fig. 1 .

Fig. 5 is a sectional view of the flexible flat cable structure of Fig. 4 along line A-A'.

FIG. 6 is a schematic structural diagram of the first shielding layer, the first shielding layer and the signal line according to the embodiment of the present invention.

The realization of the purpose, functional characteristics and advantages of the embodiments of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

【Detailed ways】

In order to further understand the features, technical means, and achieved specific functions and objectives of the present invention, more specific embodiments are enumerated, followed by drawings and drawing numbers for detailed description as follows.

The following descriptions of the various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention can be practiced. The directional terms mentioned in the present invention, such as "up", "down", "front", "back", "left", "right", "top", "bottom", "horizontal", "vertical", etc. , are for orientation only with reference to the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, but not to limit the present invention.

Please refer to Figures 1 to 4 together, Figure 1 is an exploded view of the flexible flat cable electrical connector fixing structure 1 of the present invention, Figure 2 and Figure 3 are the different fixing structures 1 of the flexible flat cable electrical connector in Figure 1 Combination diagram of perspectives. FIG. 4 is a top view of the flexible flat cable electrical connector fixing structure 1 in FIG. 1 . The flexible flat cable electrical connector fixing structure 1 includes an electrical connector 10 and a flexible flat cable structure 20 . The flexible flat cable structure 20 is inserted into the electrical connector 10 . The electrical connector 10 may be a connector conforming to specifications such as HDMI/USB3.0/USB3.1/Display Port/SATA with a data rate greater than 1 Gb/s.

The electrical connector 10 includes a base 12 , a circuit board 14 , a spacer 15 , terminals 16 and a housing 18 . The spacer 15 is assembled on the base 12 , and the spacer 15 has a plurality of receiving grooves 152 . The circuit board 14 has several conductive parts 142 and several connecting parts 144 , and the several conductive parts 142 are electrically connected to corresponding connecting parts 144 . One ends of the plurality of terminals 16 pass through the corresponding receiving slots 152 and are connected to the plurality of connecting portions 144 . The shell 18 is assembled to the base 12 .

Please refer to FIG. 5 . FIG. 5 is a cross-sectional view of the flexible flat cable structure 20 of FIG. 4 along line A-A'. The flexible flat cable structure 20 includes several transmission line sets 21 a , 21 b and a second insulating jacket 242 . Several transmission line groups 21a, 21b are arranged parallel to each other. Two adjacent transmission line groups 21a maintain a distance D1, two adjacent transmission line groups 21b maintain a distance D2, and adjacent transmission line groups 21a, 21b maintain a distance D3. The intervals D1-D3 can be set to be all equal or any two of them equal or all unequal as required. The transmission line set 21 a may include one or two signal lines 22 , a first shielding layer 251 , a first ground conductor 261 and a second shielding layer 252 . The transmission line set 21 b includes two signal lines 22 , a first shielding layer 251 , a first ground conductor 261 , a second ground conductor 262 and a second shielding layer 252 . In other embodiments, the transmission line groups 21 a, 21 b may include more than three signal lines 22 . Each signal line 22 includes a signal conductor 221 and a first insulating jacket 241 . Several signal conductors 221 of several transmission line groups 21a, 21b are arranged parallel to each other. Several signal conductors 221 can be used to transmit power or data signals as required. The signal conductors 221 can be single-core circular conductors or multi-core circular conductors. The conductors are twisted in pairs. The first insulating jacket 241 covers the signal conductor 221 . The first shielding layer 251 surrounds the signal wires 22 and contacts the first insulating jacket 241 of each signal wire 22 . In the transmission line set 21a, the first ground conductor 261 is located on one side of the signal line 22 and contacts the first shielding layer 251 for transmitting ground voltage. In the transmission line group 21b, the first ground conductor 261 and the second ground conductor 262 are respectively located on two sides of the two signal lines 22 and contact the first shielding layer 251 for transmitting the ground voltage. The second shielding layer 252 surrounds and contacts the first ground conductor 261 and the first shielding layer 251 . The second insulating jacket 242 covers the second shielding layer 252 of the plurality of transmission line groups 21a, 21b.

In some transmission line groups 21a, 21b, the first insulating jackets 241 of adjacent signal lines 22 are in contact with each other. In addition, there is a buffer space R1 between the signal lines 22 and the first shielding layer 251 of part of the transmission line groups 21a, 21b. When the flexible flat cable structure 20 is bent or squeezed, the buffer space R1 can increase the flexibility of the flat cable.

In each transmission line group 21 a, 21 b, there is a buffer space R2 between the first ground conductor 261 , the first shielding layer 251 and the second shielding layer 252 . There is also a buffer space R2 between the second ground conductor 262 , the first shielding layer 251 and the second shielding layer 252 . When the flexible flat cable structure 20 is bent or squeezed, the buffer space R2 can increase the flexibility of the flat cable.

In this embodiment, part of the transmission line set 21 includes two signal lines 22 and one ground line 261 . The ground wire 261 is covered by the second insulating jacket 242 . The metal shielding layer 26 is used to isolate the first insulating jacket 241 and the second insulating jacket 242 , and the metal shielding layer 26 forms a metal shield for several signal lines 22 . The metal shielding layer 26 can be a metal mesh or a metal sheet. Some transmission line groups 21 may also include more than three signal lines 22 and one ground line 261 . Moreover, the signal conductors 221 of each transmission line set 21 are covered by the first insulating jacket 241 , and the first insulating jacket 241 of each transmission line set 21 is surrounded by the metal shielding layer 26 .

The signal conductors 221 of the flexible flat cable structure 20 protrude from the second insulating jacket 242 and the first insulating jacket 241 , and the first ground conductor 261 and the second ground conductor 262 protrude from the second insulating jacket 242 . When the flexible flat cable structure 20 is inserted into the electrical connector 10 , the protruding signal conductor 221 , the first ground conductor 261 and the second ground conductor 262 can electrically contact the corresponding conductive portion 142 of the circuit board 14 .

Please refer to FIG. 6 . FIG. 6 is a schematic structural diagram of the first shielding layer 251 , the first shielding layer 251 and the signal line 22 according to an embodiment of the present invention. The first shielding layer 251 includes a first conductive layer 2511 and an isolation layer 2512 . The second shielding layer 252 includes a second conductive layer 2522 and a third conductive layer 2523 . Preferably, the second shielding layer 252 further includes a bonding layer 2524 . When materials with different conductive properties are used for the second conductive layer 2522 and the third conductive layer 2523, the connecting layer 2524 can be used to isolate the second conductive layer 2522 and the third conductive layer 2523, and also facilitate the connection between the second conductive layer 2522 and the third conductive layer. 2523 are respectively disposed on opposite sides of the connection layer 2524 . The third conductive layer 2523 contacts the second insulating jacket 242 . The first conductive layer 2511 is in contact with the second shielding layer 252 , and the isolation layer 2512 covers the first insulating jacket 241 . The isolation layer 2512 is made of non-conductive material and is used to isolate the signal line 22 from the first conductive layer 2511 . The second conductive layer 2522 contacts the first ground conductor 261 and the first conductive layer 2511 . The third conductive layer 2523 contacts the second insulating jacket 242 . The first conductive layer 2511 , the second conductive layer 2522 and the third conductive layer 2523 may be thin films or grids formed of conductive metals (such as aluminum, copper, silver) for reflecting and absorbing electromagnetic waves.

Since the first ground conductor 261 and the second ground conductor 262 contact the first conductive layer 2511 of the first shielding layer 251 and the second conductive layer 2522 of the second shielding layer 252 at the same time, the first ground conductor 261 and the second ground conductor 262 Relatively stable. In addition, the first conductive layer 2511 of the first shielding layer 251 forms a metal shield for the surrounding signal line 22 to prevent the signal transmitted by the signal line 22 from being interfered. In addition, the second shielding layer 252 forms a metal shield for the surrounding signal wires 22 , which can further increase the anti-interference ability of the signal wires 22 .

The materials of the first insulating jacket 241 and the second insulating jacket 242 may be different. Preferably, the first insulating jacket 241 and the second insulating jacket 242 can be polyethylene (polyethylene, PE), polyvinylchloride (polyvinylchloride, PVC), thermoplastic elastomer (Thermoplastic Elastomer, TPE), thermoplastic polyurethane (Thermoplastic Polyurethane, TPU), thermoplastic rubber (thermoplastic rubber, TPR), thermoplastic polyolefin (Thermoplastic Polyolefin, TPO), polyurethane (Polyurethane, PUR), polypropylene (Polypropylene, PP), polyolefin (Polyolefins, PO), PVDF (PolyVinyliDene Fluoride) , ethylene-chlorotrifluoroethylene copolymer (Ethylene-chlorotrifluoroethylene copolymer, ECTFE), ethylene-tetrafluoroethylene copolymer (ethylene-tetra-fluoro-ethylene, ETFE), Teflon polyperfluoroethylene propylene resin (Teflon Fluorinated ethylene Propylene, Teflon FEP), polytetrafluoroethylene (Polytetrafluoroethene, PTFE), Teflon (Teflon) or nylon (Nylon) and other heat-resistant insulating materials. The signal conductor 221 , the first ground conductor 261 and the second ground conductor 262 may be extremely thin tinned flat copper wires.

The flexible flat cable structure and the flexible flat cable electrical connector fixing structure of the embodiments of the present invention divide all signal lines into several transmission line groups, and each transmission line group includes a first shielding layer, a second shielding layer and a grounding conductor. The first shielding layer and the second shielding layer have the ability to reflect and absorb electromagnetic waves. The ground conductor is disposed between the first shielding layer and the second shielding layer such that both the first shielding layer and the second shielding layer are in contact with the grounding conductor, so that the grounding conductor is in contact with the first shielding layer and the second shielding layer. The double-side contact of the second shielding layer will make the shielding grounding structure of the flexible flat cable relatively stable. The signal wires of each transmission line group wrap the first shielding layer and the second shielding layer respectively so that the flexible flat cable structure has better EMI resistance than the traditional flat cable, so the flexible flat cable structure of the present invention It can improve the EMI problem generated by traditional flat cables during signal transmission.

In summary, although the present invention has been disclosed above with a preferred embodiment, the preferred embodiment is not intended to limit the present invention, and those of ordinary skill in the art may, without departing from the spirit and scope of the present invention, Various changes and modifications are made, so the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims (10)

1. A flexible flat cable structure, characterized in that it comprises: Several transmission line groups are arranged in parallel with each other, and a gap is maintained between each transmission line group and the adjacent transmission line group. Each transmission line group includes: At least one signal line, each signal line includes: a signal conductor for the transmission of data signals or power; and a first insulating jacket covering the signal conductor; a first shielding layer surrounding the signal lines and contacting the first insulating jacket of each signal line; a first ground conductor, located on one side of the signal line and in contact with the first shielding layer, for transmitting ground voltage; and A second shielding layer surrounds and contacts the first ground conductor and the first shielding layer; and a second insulating jacket covers the second shielding layers of the transmission line groups. 2 . The flexible flat cable structure according to claim 1 , wherein, in some transmission line groups, the first insulating jackets of adjacent signal lines of at least two of the signal lines are in contact with each other. 3 . The flexible flat cable structure according to claim 1 , wherein there is a buffer space between at least two of the signal lines of the partial transmission line group and the first shielding layer. 4 . 4. The flexible flat cable structure according to claim 1, wherein some transmission line groups further comprise a second ground conductor, and the first ground conductor and the second ground conductor are respectively located at two ends of the two signal lines. side and contacts the first shielding layer for transmission of ground voltage. 5 . The flexible flat cable structure according to claim 4 , wherein there is a buffer space between the second ground conductor, the first shielding layer and the second shielding layer of each transmission line group. 6 . The flexible flat cable structure according to claim 1 , wherein there is a buffer space between the first ground conductor, the first shielding layer and the second shielding layer of each transmission line group. 7. The flexible flat cable structure according to claim 1, wherein the first shielding layer comprises: a first conductive layer contacting the second shielding layer; and An isolation layer covers the first insulating jacket. 8. The flexible flat cable structure according to claim 7, wherein the second shielding layer comprises: a second conductive layer contacting the first ground conductor and the first conductive layer; and A third conductive layer is in contact with the second insulating jacket. 9. The flexible flat cable structure according to claim 1, wherein the first insulating jacket and the second insulating jacket are made of polyethylene (polyethylene, PE), polyvinylchloride (polyvinylchloride, PVC), thermoplastic Elastomer (Thermoplastic Elastomer, TPE), Thermoplastic Polyurethane (TPU), Thermoplastic Rubber (TPR), Thermoplastic Polyolefin (TPO), Polyurethane (PUR), Polypropylene (PP) , Polyolefins (Polyolefins, PO), PVDF (PolyVinyliDene Fluoride), ethylene-chlorotrifluoroethylene copolymer (Ethylene-chlorotrifluoroethylene copolymer, ECTFE), ethylene-tetrafluoroethylene copolymer (ethylene-tetra-fluoro-ethylene, ETFE) , Teflon Fluorinated ethylenepropylene (Teflon FEP), polytetrafluoroethylene (PTFE), Teflon or nylon (Nylon). 10. A flexible flat cable electrical connector fixing structure, comprising: An electrical connector comprising: a base; A spacer is assembled on the base, and the spacer has several receiving grooves; A circuit board has several conductive parts and several connecting parts, and the several conductive parts are electrically connected to corresponding connecting parts; a plurality of terminals, one end of the plurality of terminals passes through the corresponding receiving groove and is connected to the plurality of connecting parts; and a shell assembled on the base; and A flexible flat cable structure, characterized in that the flexible flat cable structure comprises the flexible flat cable structure according to any one of claims 1-9, wherein the first ground conductor or the second ground conductor and the signal Conductors are connected to the plurality of conductive parts.