CN216161479U

CN216161479U - Improved structure of flat cable

Info

Publication number: CN216161479U
Application number: CN202122264954.1U
Authority: CN
Inventors: 叶时堃
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2022-04-01
Anticipated expiration: 2031-09-17

Abstract

The utility model relates to a flat cable improved structure, which comprises a flat cable, wherein the flat cable is sequentially laminated with a conductor layer, a foaming body layer, a metal layer and an insulating layer, the conductor layer comprises a plurality of signal wires which are spaced from one another, and the foaming body layer is a polyethylene layer; therefore, the improved structure of the flat cable can enable the flat cable to still maintain the advantage of high-speed transmission efficiency under the condition of thinning the thickness.

Description

Improved structure of flat cable

Technical Field

The present invention relates to signal transmission technology, and more particularly, to an improved structure of a flat cable capable of maintaining high-speed transmission efficiency even when the thickness of the flat cable is reduced by changing the material of a foam layer of the flat cable.

Background

The improved structure of the general flat cable comprises a flat cable (such as signal transmission lines of PCIE standard bus and SATA standard bus used for computers) and connectors respectively arranged at two ends of the flat cable, wherein the connectors are electrically connected with the flat cable and connected to corresponding connectors (such as male and female corresponding connectors) of external equipment, and signals are transmitted between the external equipment through the signal lines in the flat cable and the connectors.

Referring to fig. 1 and 2, fig. 1 is a plan view of a conventional flat cable, and fig. 2 is a cross-sectional view taken along a section of fig. 1A-a. As shown in fig. 1 and 2, the conventional flat cable 9 is laminated with a conductive layer 91, a foam layer 92, a metal layer 93, an insulating layer 94, and the like, and the conductive layer 91 is provided with a plurality of signal lines 911 and a plurality of ground lines 912. Conventionally, two signal lines 911 are matched with a ground line 912, so as to be repeatedly arranged into a flat cable 9 with a standard width, for example, a flat cable 9 with a standard width of forty-eight lines or seventy-two lines.

As described above, since the conductive layer 91 of the conventional flat cable 9 has the grounding line 912, the width of the signal line 911 is limited under the condition that the flat cable 9 has a standard width, thereby reducing the transmission rate. Therefore, the structure of the flat cable 9 must be designed properly, and the so-called skin effect and characteristic impedance must be considered in design.

The skin effect is also called as skin effect, and it is a phenomenon that when there is an alternating current or an alternating electromagnetic field in a conductor (such as the signal line 911), the current distribution inside the conductor is not uniform, and the current density inside the conductor exponentially decays with the distance from the surface of the conductor, that is, the current inside the conductor is concentrated on the surface of the conductor, when viewed from a cross section perpendicular to the current direction, almost no current flows through the center portion of the conductor, and only the current flows at the edge portion of the conductor, in short, the current is concentrated on the skin portion of the conductor. Since the skin effect causes the alternating current to pass only through the surface of the conductor, the current generates a thermal effect only on the surface of the conductor, and thus, for example, in the steel industry, the skin effect can be utilized to surface quench steel, increasing the hardness of the steel surface. Methods for reducing the skin effect can be used, for example, by so-called litz wires, i.e. by winding a plurality of metal wires around one another, so that the electromagnetic field is distributed relatively uniformly; or the solid conductor can be replaced by a hollow conductor tube, and the middle of the hollow conductor tube is supplemented with an insulating material.

The characteristic impedance refers to resistance in ohms which is encountered when a high-frequency signal or an electromagnetic wave propagates through a conductor. The fluctuation of the impedance values in the conductors must be controlled so that signals can be transmitted at a correct speed, and there are different impedance calculation formulas for transmission lines formed by different types of conductors (such as coaxial transmission lines, line-type transmission lines, microstrip transmission lines, coplanar transmission lines, etc.). The impedance control can be achieved by changing different design conditions, such as changing the material, thickness and dielectric constant of the foam layer in the transmission line.

However, the conventional flat cable 9 has a relatively thick thickness for improving the transmission efficiency, for example, for controlling the impedance, due to the influence of the material used in the flat cable 9.

SUMMERY OF THE UTILITY MODEL

In order to solve the above-mentioned problem of increasing the thickness of the conventional flat cable due to the use of material, the present invention provides an improved flat cable structure to change the material of the foam layer of the flat cable so as to maintain the high-speed transmission efficiency of the flat cable even when the thickness of the flat cable is reduced.

The technical means adopted by the utility model are as follows.

The flat cable improved structure provided by the utility model comprises a flat cable, wherein the flat cable is sequentially laminated with a conductor layer, a foaming body layer, a metal layer and an insulating layer, the conductor layer comprises a plurality of signal lines which are spaced from each other, and the foaming body layer is made of Polyethylene (PE).

Optionally, in a non-limiting embodiment, the flat cable further includes a membrane layer laminated between the conductive layer and the foam layer.

Optionally, in a non-limiting embodiment, the material of the film layer is Polyethylene Terephthalate (PET).

Optionally, in a non-limiting embodiment, the flat cable is further laminated with the skin layer, the foam layer, the metal layer and the insulating layer sequentially from the conductive layer to the upper and lower sides.

Optionally, in a non-limiting implementation example, the conductive layer and the film layer, the film layer and the foam layer, the foam layer and the metal layer, and the metal layer and the insulating layer are respectively bonded by using an adhesive layer.

Optionally, in a non-limiting embodiment, the conductive layer further includes a plurality of ground lines spaced apart from each other.

Alternatively, in a non-limiting embodiment, the plurality of signal lines are arranged in a single row.

Alternatively, in a non-limiting embodiment, the plurality of signal lines are arranged in two rows.

Optionally, in a non-limiting embodiment, the Flat Cable is a Flexible Flat Cable (FFC).

The technical effects produced by the present invention are as follows.

The improved structure of the flat cable is structurally designed to use a polyethylene layer as the foam layer of the flat cable, and because the polyethylene has a small dielectric constant, the obtained impedance value can be increased and the thickness of the opposite flat cable can be reduced according to the calculation of an impedance formula. In other words, the flat cable can maintain high-speed transmission efficiency even when the thickness is reduced.

Drawings

Fig. 1 is a plan view of a conventional flat cable.

Fig. 2 is a cross-sectional view taken at section a-a of fig. 1.

Fig. 3 is a perspective view of the first preferred embodiment of the present invention.

Fig. 4 is a cross-sectional view of the first preferred embodiment of the present invention.

Fig. 5 is a cross-sectional view of a second preferred embodiment of the present invention.

Fig. 6 is a cross-sectional view of a third preferred embodiment of the present invention.

Fig. 7 is a cross-sectional view of a fourth preferred embodiment of the present invention.

Description of the figure numbers:

1: improved structure of flat cable

2: flat cable

21: conductive layer

211: signal line

212: grounding wire

22: metal layer

23: insulating layer

24: foam layer

25: glue layer

26: coating layer

3: connector with a locking member

5: circuit board

51: signal conducting wire

52: ground conducting wire

7: signal transmission device

9: flat cable

91: conductive layer

911: signal line

912: grounding wire

92: foam layer

93: metal layer

94: an insulating layer.

Detailed Description

Please refer to fig. 3, which is a perspective view of a first preferred embodiment of the present invention. Fig. 3 shows a signal transmission device 7, which includes a flat cable improved structure 1, and the flat cable improved structure 1 includes a flat cable 2, in this embodiment, the flat cable 2 is a Flexible Flat Cable (FFC), although not limited thereto, and the flat cable 2 may also be a Flexible Printed Circuit (FPC), for example.

In addition, the signal transmission device 7 further includes a connector 3 and a circuit board 5, wherein the circuit board 5 includes a plurality of signal conducting wires 51 and a plurality of ground conducting wires 52 arranged at intervals, the circuit board 5 is electrically connected to the flat cable 2, and the connector 3 is connected to a connection position of the flat cable 2 and the circuit board 5 and thereby electrically connected to other electrical devices (not shown).

Fig. 4 is a sectional view of the first preferred embodiment of the present invention. As shown in fig. 4, the flat cable 2 is formed by sequentially stacking a film layer 26 (e.g. PET material), a foam layer 24, a metal layer 22 and an insulating layer 23 from a conductive layer 21 to the upper and lower sides, and the layers are bonded by an adhesive layer 25; in detail, the adhesive layers 25 are respectively used to bond the conductive layer 21 and the film layer 26, the film layer 26 and the foam layer 24, the foam layer 24 and the metal layer 22, and the metal layer 22 and the insulating layer 23.

As shown in fig. 4, the conductive layer 21 of the flat cable 2 includes a plurality of signal lines 211 spaced apart from each other, and in the embodiment, the plurality of signal lines 211 are arranged in a single row. The foam layer 24 of the flat cable 2 is a polyethylene layer.

The following formula (I) is a transmission characteristic impedance formula of the flat cable improved structure:

wherein Z₀Is characteristic impedance (characteristic impedance), epsilon_rIs the dielectric constant, W is the line width, H is the height of the insulating layer, and T is the thickness of the conductive layer. In the flat cable improved structure 1, the foam layer 24 of the flat cable 2 is changed to a polyethylene layer, and the material property of the polyethylene layer shows that the dielectric constant of polyethylene is small, and the impedance value is increased by calculation according to the impedance formula for the flat cable 2, and the thickness of the flat cable 2 is relatively reduced (small) by calculation according to the calculation formula. In other words, the foam layer 24 of the flat cable 2 is made of polyethylene, so that the flat cable 2 can maintain high-speed transmission efficiency even when the thickness is reduced.

Fig. 5 is a sectional view of a second preferred embodiment of the present invention. In the present embodiment, the main structure is the same as that of the first preferred embodiment, and the difference is that the plurality of signal lines 211 of the conductor layer 21 of the flat cable 2 are arranged in two rows in the present embodiment.

Please refer to fig. 6, which is a cross-sectional view of a third preferred embodiment of the present invention. In the present embodiment, the main structure is the same as the first preferred embodiment, and the difference is that the conductive layer 21 of the flat cable 2 further includes a plurality of ground lines 212 spaced from each other, and the plurality of ground lines 212 and the plurality of signal lines 211 arranged in a single row are spaced from each other, that is, one signal line 211, one ground line 212, and another signal line 211 are sequentially arranged.

Fig. 7 is a sectional view of a fourth preferred embodiment of the present invention. In the present embodiment, the main structure is the same as the second preferred embodiment, and the difference is that the conductive layer 21 of the flat cable 2 further includes a plurality of grounding lines 212 spaced from each other, and the plurality of grounding lines 212 and the plurality of signal lines 211 arranged in two rows are spaced from each other, that is, a pair of signal lines 211, a grounding line 212, and another pair of signal lines 211 are sequentially arranged.

Claims

1. An improved flat cable structure, comprising:

a flat cable (2) sequentially laminated with a conductor layer (21), a foam layer (24), a metal layer (22) and an insulation layer (23), wherein the conductor layer (21) comprises a plurality of signal lines (211) spaced from each other, and the foam layer (24) is a polyethylene layer.

2. The flat cable improvement structure according to claim 1, wherein the flat cable (2) further comprises a membrane layer (26) laminated between the conductive layer (21) and the foam layer (24).

3. The flat cable improved structure according to claim 2, wherein the material of the coating layer (26) is polyethylene terephthalate.

4. The flat cable improvement structure according to claim 2, wherein the flat cable (2) is sequentially laminated with the membrane layer (26), the foam layer (24), the metal layer (22) and the insulating layer (23) from the conductor layer (21) to the upper and lower sides.

5. The flat cable improvement structure according to claim 4, wherein a glue layer (25) is respectively used to bond the conductive layer (21) and the cover film layer (26), the cover film layer (26) and the foam layer (24), the foam layer (24) and the metal layer (22), and the metal layer (22) and the insulating layer (23).

6. The flat cable improvement structure according to any one of claims 1 to 5, wherein the conductive layer (21) further comprises a plurality of ground lines (212) spaced apart from each other.

7. The flat cable improved structure as claimed in any one of claims 1 to 5, wherein the plurality of signal lines (211) are arranged in a single row.

8. The flat cable improved structure as claimed in any one of claims 1 to 5, wherein the plurality of signal lines (211) are arranged in two rows.

9. The flat cable improvement structure according to any one of claims 1 to 5, wherein the flat cable (2) is a flexible flat cable.