JPS63141211A - Flat cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a flat cable used as internal wiring of electronic devices such as computers, and more specifically, a flat cable with excellent wiring workability, electrical properties, and terminal processing workability. This relates to flat cables.

[Prior Art] Internal wiring materials for electronic devices such as computers are required to have characteristics such as wiring workability, electrical properties, and terminal processing workability, and the applicant has developed a method to meet these requirements. We have previously proposed two cable structures.

In other words, this cable consists of an insulated conductor consisting of a central conductor, a highly foamed fluororesin insulator provided around its outer periphery, and a solid fluororesin insulator layer coated on the outer periphery, and a drain wire attached vertically to the insulated conductor. , a plurality of cable cores each consisting of a shield tape layer provided on the outer periphery and a thermoplastic resin jacket layer provided on the outermost periphery are arranged in parallel, and adjacent cores are fused and integrated.

This cable uses fluororesin as an insulator, so it has a low dielectric constant, and since it is made of foam, it has even better electrical properties.The drain wire is in contact with the shield tape, so the cable is terminally processed. It has good workability, and
The core is flattened, making wiring work easier and achieving the desired results.

The reason why a solid fluororesin insulator layer is provided as an insulator around the outer periphery of the highly expanded fluororesin insulator layer is as follows.

In other words, when processing the terminals of this cable, a cutting machine is used to remove the jacket and the shield tape at the same time.In order to further lower the dielectric constant, the cable is made of highly foamed insulators with increased degree of foaming. In this case, when the teeth of the cutting machine are inserted into the jacket, the soft foam insulation deforms and absorbs the force of the cutting machine, making it difficult to peel off the shield layer and the jacket at the same time.

Furthermore, if the insulator is foamed to a high degree of foaming of 50% or more, air bubbles will be present on the surface of the insulator, and the electrical characteristics will change depending on the state of the air bubbles, resulting in the drawback that the electrical characteristics will not be stable.

The solid fluororesin insulation layer is intended to solve these drawbacks.The presence of the solid fluororesin insulation layer allows the jacket and shield layers to be removed all at once using a cutting machine, and the surface becomes smooth. The electrical characteristics are also stable.

[Problems to be Solved by the Invention] Incidentally, in recent years, electronic devices such as computers have become more complex, and in this case, waveform stability and characteristics with less signal attenuation in the high frequency region are required. That will happen.

FIG. 4 shows the transmittance characteristics of the flat cable with respect to frequency, and B and C show the characteristics of the flat cable previously proposed by the applicant.

Here, characteristic B is a case in which the shield tape layer is provided by winding, and characteristic C is a case in which the shield tape is provided by vertically attaching.

As is clear from this figure, the conventional flat cable (characteristic B) provided with a shield layer by winding had a drawback of large signal attenuation in the high frequency region.

The reason for this is thought to be that the shielding tape is simply wound, resulting in poor stability and particularly poor signal attenuation in the high frequency range.

On the other hand, a structure in which the shield layer is provided vertically (characteristic C)
Although the signal attenuation in the high frequency range was improved, the disadvantage was that the waveform was greatly disturbed.

The reason for this is also considered to be that the structure is such that the shield tape is simply attached vertically, resulting in poor stability and disturbances in the waveform, especially in the high frequency range.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat cable for electronic equipment that eliminates the drawbacks of the prior art described above, has good wiring workability and terminal processing workability, and has excellent electrical characteristics, especially in a high frequency region.

[Means for solving the problem] In other words, the gist is: a central conductor, a highly foamed fluororesin insulator layer coated on the outer periphery by extrusion, and a solid fluororesin insulator coated on the outer periphery. an insulated conductor consisting of a layer, a drain wire longitudinally attached to at least one side of the insulated conductor, a shielding tape layer longitudinally attached to the outer periphery of the insulated conductor, a pressing tape layer wound around the outer periphery, and The above-mentioned shield tape is made by arranging a plurality of cores made of a thermoplastic resin jacket extruded on the outermost periphery in parallel, and heat-sealing only the surfaces of adjacent cores at least at predetermined intervals in the longitudinal direction. , is a laminate tape consisting of a metal tape, a reinforcing polyester tape, and a coating layer provided on the surface of the polyester cheese, and the presser tape is provided with a coating layer on both sides, and each of the coating layers is coated with a jacket. The flat cable is characterized by being constructed so that the shield tape, presser tape, and jacket are fused and integrated by being melted by the heat during coating.◇ In the above, the center conductor is Silver-plated annealed copper wire is used.

That is, the flat cable of the present invention uses a fluororesin as an insulator, and is plated with silver to prevent the conductor from discoloring at the high temperatures during extrusion of the fluororesin.

As the highly foamed fluororesin layer, PFA, FEP, or E-TFE having a foaming degree of 50% or more, preferably 60% or more is provided by extrusion.

The solid fluororesin layer is PFA, FEP or E-T.
FE is provided by extrusion, and even if this full fluororesin layer is extruded and coated at the same time as the highly expanded fluororesin layer,
Alternatively, they may be provided separately.

Here, the solid fluororesin insulator layer must be provided sufficiently thinner than the foamed fluororesin insulator layer.

In other words, the solid fluororesin insulator layer is good for the purpose of stabilizing the electrical characteristics if it covers the surface of the foamed insulator layer to make the surface smooth, but making the solid fluororesin layer thicker is not enough. This is not preferable because it increases the dielectric constant.

Although this thickness depends on the manufacturing technology, it is preferably 0.10 mm or less, particularly preferably 0.06 mm or less.

The drain wire may be provided on at least one side of the insulated conductor, and may be provided on both sides of the insulated conductor if necessary.

The shielding tape used is copper tape, tin-plated copper tape, or laminate tape consisting of a metal tape such as aluminum tape, polyester tape, and a coating layer of vinyl-based resin, and is used with the metal tape side on the inside. It will be done.

A polyester tape is used as the pressing tape on the shield tape, and both sides of the tape are coated with a vinyl resin.

The coating layer provided on the surface of the polyester tube for the shield and presser spring is melted by the heat during coating the jacket, and the shield tape, presser tape, and the entire jacket are fused and integrated.

When using aluminum tape as the metal tape, 25
A thickness of about 10 μm is used.

The polyester chive is for reinforcing the metal tape, and preferably has a thickness of 6 μm or less, preferably 4 μm or less.

That is, the thicker the polyester tape, the higher its strength and the easier it is to handle during production, but if it is too thick, it will not be possible to peel off the shield tape and the jacket at the same time during terminal processing.

According to experiments, when the polyester thickness was 25μ, it could not be peeled off at all, and when it was 12μ, only a portion could be peeled off.

On the other hand, if the thickness is 6μ or less, 100% peeling is possible, and it is preferable to use a polyester tube having a thickness of 6μ or less, preferably 4μ.

The jacket is provided by extrusion coating of thermoplastic resin.

As a method for heat-sealing the cores arranged in parallel, it is preferable that only the upper and lower surfaces of the cores be heat-sealed, and the contact portions between adjacent cores be non-sealed.

In other words, when fusing the core, only the top and bottom surfaces are heated to a temperature above the melting point in order to heat-fuse the jacket, but at this time, the volume of the jacket changes significantly and the dimensional accuracy between the center conductors is affected. To prevent this, it is preferable to heat-seal only the upper and lower surfaces.

[Embodiments of the Invention] Next, an embodiment of the flat cable of the present invention will be further described with reference to the accompanying drawings.

In FIG. 1, 1 is a central conductor, and a foamed insulator 2 and a solid insulator 3 are sequentially provided on the outer periphery of the central conductor, forming an insulated conductor.

Reference numeral 4 denotes a drain wire attached vertically to the insulated conductor, and a shielding tape 5 is also vertically twisted around the outer periphery of the drain wire.

6 is a press-wound polyester tape layer from above the vertically twisted shield tape.

7 is a jacket provided on the outermost periphery of these cables, and constitutes a cable core.

Here, the center conductor 1 and drain wire 4 are 0.2
A silver-plated annealed copper wire with a diameter of 54 mm is used.

The foamed insulator 2 is made of PFA with a foaming degree of 60% or more, and is extruded to have an outer diameter of about 0.57 mm.

E-TFE is used as the solid insulator 3, and its thickness is about 0.05 mm.

As the shield tape 5, a laminate tape of polyester and aluminum is used, the aluminum has a thickness of 20μ, the polyester has a thickness of 4μ, and the polyester surface is thinly coated with a vinyl-based resin.

Further, as the presser tape 6 to be applied over the shield, polyester having a thickness of 6 μm is used, and both surfaces of the polyester are thinly coated with a vinyl-based resin.

Jacket 7 is made of extruded vinyl and has a width of 1
．． 27±0. 07 (mm) thickness is 1.20±0
．． 1 (mm).

A plurality of cable cores formed in this manner are arranged in parallel as shown in FIG. 2, and only the surfaces of adjacent cores are integrated by fusion.

According to the flat cable of this embodiment, which is constructed in this way, characteristics of characteristic impedance Zo-55±5 (Ω) and transmission speed Td-3.9±0.1 (n5ac/m) are obtained, and the conductor The distance between them is 1.27±0. 07 (m
m).

FIG. 3 shows an example of a device for measuring the electrical characteristics of the cable of this embodiment, which measures transmittance in which a signal input manually from one end of the measurement sample is output to the other end.
FIG. 4 shows the measurement results.

As is clear from Fig. 4, the cable of this embodiment (characteristic A
) has extremely low signal attenuation in the high frequency range compared to the conventional product simply wrapped with shield tape (characteristic B).

This has a structure in which the tape is wrapped around the vertically attached shield, and it proves that the contact between the shield tape and the drain wire is good. ), it can be seen that the waveform disturbance is extremely small.

In particular, waveform disturbances in the high frequency range will become a problem as electronic devices such as computers become faster in the future.
It is clear that the product of the present invention has good characteristics.

[Effects of the Invention] As explained above, according to the present invention, it is possible to provide a cable for internal wiring of electronic equipment which has excellent electrical properties particularly in the high frequency range and excellent terminal processing workability, It has tremendous value.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing one embodiment of the core constituting the flat cable of the present invention, FIG. An explanatory diagram showing an example of a device for measuring electrical characteristics, and FIG. 4 is a characteristic diagram comparing the characteristics of the cable of the present invention and a conventional cable. 1: Conductor, 2: Highly foamed fluororesin insulation layer, 3: Full fluororesin insulation layer, 4: Drain wire, 5: Vertical shield tape layer, 6: Shield pressing tape layer, 7 Nivinyl jacket layer. No. 1 Old No. 2 No. 3 No. J fixed 7〉Pull (L-2, 4 area) No. 4 Concave! ;O650+0”;Q 1450
2050 Town Yoshiki f (MHx)□

Claims (1)

[Claims] (1) An insulated conductor consisting of a central conductor, a highly foamed fluororesin insulation layer coated on the outer periphery by extrusion, and a solid fluororesin insulation layer coated on the outer periphery, and at least one side of the insulated conductor. A core consisting of vertically attached drain wires, a shielding tape layer attached longitudinally to their outer periphery, a pressing tape layer wound around the outer periphery, and a thermoplastic resin jacket extruded and coated on the outermost periphery. are arranged in parallel, and only the surfaces of adjacent cores are thermally fused at least at predetermined intervals in the longitudinal direction. It is a laminated tape with a coating layer provided on it, and
The above-mentioned presser tape is provided with coating layers on both sides, and each of the coating layers is configured to be melted by the heat when covering the jacket, and the shield tape, presser-wrap tape, and jacket are fused and integrated. A flat cable featuring