KR101207414B1 - Flexible flat cable - Google Patents

Abstract

PURPOSE: A flexible flat cable is provided to improve flexibility by removing a dielectric film for matching impedance. CONSTITUTION: A flexible flat cable includes a plurality of conducting wires(11), first and second insulating films(13,15), a third insulating film(17), a conductive metal layer(21), and a fourth insulating film(23). Both ends in the longitudinal direction of the conducting wire are planted by Ni and Au. The first and second insulating films are bonded to each other by a laminate process. The third insulating film is attached on the surface of the second insulating film. The conductive metal layer is made of conductive metal such as aluminum, silver, gold, copper, nickel, molybdenum, nickel or tin on the upper part of the third insulating film.

Description

Flexible Flat Cable {Flexible Flat Cable}

The present invention relates to a flexible flat cable.
In general, a flexible flat cable (FFC) is used as a relay cable for electrically connecting each component in various electronic device products such as a printer, a scanner, a TV, a PC, a notebook, a monitor, and a multifunction device. FFC has excellent flexibility, so it can be used for operation such as bending, and it is used in a wide range of fields because manufacturing cost is cheaper than Flexible Printed Circuit (FPC). have.

By the way, flexible flat cables have never been required to have electrical properties such as characteristic impedance. For this reason, flexible flat cables satisfy the required specifications by simply crimping insulating films made of synthetic resin on both sides by interposing a plurality of conductors arranged in parallel at a predetermined interval so that conductive metals are formed in the form of conductors and do not come into contact with adjacent ones. It was possible.

On the other hand, in recent years, various kinds of electronic apparatuses such as a notebook-type personal computer or a digital scanner that realizes high-definition image quality have been developed, so that a high-speed signal transmission has been required. In addition, as digitization progresses in other electronic apparatus products, it has become a technical problem that speeding up of signal transmission is indispensable.

In general, a signal transmission cable is required to be compatible with high-speed transmission since a signal transmission speed becomes high and a resistance to noise is reduced. However, in such a cable, there is a problem of unnecessary electromagnetic interference (EMI) at the same time as increasing the signal transmission speed. That is, in signal transmission, as the signal becomes a high frequency, unnecessary electromagnetic waves are easily leaked and injected into adjacent cables or the like, which causes adverse effects such as malfunction or transmission loss.

Accordingly, flexible flat cables have been developed that can shield electromagnetic waves by depositing a shielding layer made of a conductive metal layer on the surface of the insulating film or by adhering a shielding tape.

Flexible flat cable capable of shielding electromagnetic waves according to the prior art is disclosed in Korean Patent No. 10-0899107 (name of the invention: flexible flat cable).

Flexible flat cable according to the prior art is a plurality of conductive wires formed of a conductive metal arranged in parallel at a predetermined interval so as not to contact with each other and a heat-adhesive synthetic resin to be bonded to each other by laminating through the plurality of conductive wires First and second insulating films formed on one side of the plurality of wires, the first and second insulating films being shorter than the length of the plurality of wires and exposing both ends of the plurality of wires; A third insulating film adhered to one surface of the second insulating film to adjust impedance of the plurality of conductive wires, a fourth insulating film adhered to the surface of the third insulating film, and a surface of the fourth insulating film A conductive metal layer formed of a conductive metal to shield electromagnetic waves, and conductive on the conductive metal layer A conductive anti-oxidation layer formed by coating with a synthetic resin including a metal powder made of an alloy of metal or conductive metals to prevent oxidation while being electrically connected to the conductive metal layer, and formed to be shorter than a length of the first insulating film, so that the conductive And a fifth insulating film covering the anti-oxidation layer so that both ends thereof are exposed in the longitudinal direction to define the ground portion.

The above-mentioned flexible flat cable shielded electromagnetic waves by forming a conductive metal layer on which a conductive metal was deposited or plated on a fourth insulating film, and a conductive antioxidant layer for preventing oxidation on the conductive metal layer.

However, the flexible flat cable according to the prior art has a small resistance of the conductive metal layer and the conductive anti-oxidation layer to shield the electromagnetic waves, so that the thickness of the third insulating film used as the dielectric layer is needed to match the impedance of the plurality of wires, but the thickness thereof is increased. But this has caused a problem that the flexibility is reduced.

Accordingly, an object of the present invention is to provide a flexible flat cable that can improve the flexibility while reducing the thickness of the cable because no dielectric film is required to match the impedance of the plurality of wires.

A flexible flat cable according to an embodiment of the present invention for achieving the above object is a plurality of thin film formed of a conductive metal to be arranged at regular intervals so as not to contact with each other on the first insulating film and adjacent to the first insulating film A second insulating film bonded to the conductive wire and the first insulating film to cover the plurality of conductive wires and having a length shorter than that of the plurality of conductive wires to expose both ends; The third insulating film and a plurality of lines having a narrow width on the surface of the third insulating film are electrically connected to each other to shield electromagnetic waves, and are formed to be shorter than the length of the third insulating film. And a fourth insulating film covering the conductive metal layer so that both ends thereof are exposed in the longitudinal direction to define the ground portion.

In the above, the plurality of conductors are formed by any one of deposition, plating, and metal foil.

Wherein the first to fourth insulating film is nylon (nylon), polyimide (polyimide), polyvinylacetate, polyurethane (polyurethane), polyester (polyester), polyethylene (polyethylene) or polypropylene (polypropylene) It is formed of synthetic resin.

In the conductive metal layer is a conductive metal is formed by deposition or plating, wherein the conductive metal layer is formed on the third insulating film to form a release layer so as to expose the portion to form a conductive wire and then deposited or plated on the exposed portion The conductive metal layer is formed by removing the release layer, or the conductive metal layer is formed by depositing or plating the conductive metal on the third insulating film and patterning the photolithography method.

The conductive metal layer is formed by attaching a foil of the conductive metal on the third insulating film and patterning by a photolithography method.

A plurality of flexible flat cables according to another embodiment of the present invention for achieving the above object is formed of a thin film of a conductive metal to be arranged at regular intervals so as not to be in contact with each other on the first insulating film and adjacent to the first insulating film. A plurality of conductive wires, the second insulating film bonded to the plurality of conductive wires on the first insulating film and having a length shorter than the length of the plurality of conductive wires so as to expose both ends thereof, and the second insulating film. A plurality of lines having a narrow width on the surface is electrically connected to each other to shield the electromagnetic waves, and a third insulating film to cover the conductive metal layer on the second insulating film.

Therefore, the present invention does not require a dielectric film for matching impedance, so that the thickness of the cable can be reduced as well as flexibility can be improved, so it is easily folded and used in a narrow space inside the electronic device.

1 is a plan view partially cut a flexible flat cable according to an embodiment of the present invention.
2 is a cross-sectional view taken along line AA of FIG. 1.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a partial cutaway plan view of a flexible flat cable according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line A-A.

The flexible flat cable according to the present invention includes a plurality of conductive wires 11, first and second insulating films 13 and 15, a third insulating film 17, a conductive metal layer 21, and a fourth insulating film 23. It includes.

The plurality of conductive wires 11 are arranged in parallel at regular intervals so that conductive metals such as copper or tin are formed in the form of conductive wires and do not come into contact with adjacent ones. In the above, the plurality of conductive wires 11 may be plated with Ni / Au or the like at both ends in the longitudinal direction, thereby preventing the resistance from increasing by oxidizing while improving conductivity.

The first and second insulating films 13 and 15 are bonded to each other by laminating through the plurality of conductive wires 11 to protect the plurality of conductive wires 11. In the above, any one of the first and second insulating films 13 and 15, for example, the second insulating film 15 is the same as the length of the plurality of conductive wires 11 and the other, for example, 2 The insulating film 15 is formed shorter than the length of the plurality of conductive wires 11 to expose both ends of the plurality of conductive wires 11 in the longitudinal direction.

The plurality of conductive wires 11 may be formed by forming a release layer on the first insulating film 13 to expose a portion where the conductive wire is to be formed, and removing the release layer after deposition or plating. In addition, the plurality of conductive wires 11 may be formed by depositing or plating a metal to form the conductive wire on the first insulating film 13 and then patterning the same by a photolithography method. In addition, the plurality of conductive wires 11 may be formed by attaching a foil to form a conductive wire on the first insulating film 13 with an adhesive or an adhesive and then patterning the photolithography method.

The first and second insulating films 13 and 15 are formed of a heat-adhesive synthetic resin having an insulating property, heat resistance, flexibility, and recoverability while having mechanical strength such as tensile strength, and have a thickness of about 10 to 250 μm. Therefore, the first and second insulating films 13 and 15 may be made of nylon, polyimide, polyvinylacetate, polyurethane, polyester, and polyethylene. Or it may be formed of a synthetic resin such as polypropylene.

The third insulating film 17 is formed to adhere on the surface of any one of the first and second insulating films 13 and 15, for example, the second insulating film 15. The third insulating film 17 may be nylon, polyimide, polyvinylacetate, polyurethane, poly, or the like as the first and second insulating films 13 and 15. Synthetic resin such as ester, polyethylene, or polypropylene is formed to a thin thickness of about 10 to 50㎛. In the above, the third insulating film 17 uses a polyurethane, polyester, polyvinylacetate copolymer, polyvinyl acetate copolymer, acrylic copolymer and the like to firm the interlayer adhesion on the second insulating film 15 To attach. In addition, the third insulating film 17 may be attached onto the second insulating film 15 with an adhesive such as acrylic, polyurethane, or silicone.

The conductive metal layer 21 is formed on the third insulating film 17 with a thickness of about 1000 μm to 50 μm of conductive metal such as aluminum, silver, gold, copper, nickel, molybdenum, nickel, or tin. The conductive metal layer 21 shields electromagnetic waves generated from the plurality of conductive wires 11 and radiated to the outside or applied to the conductive wires 11 from the outside when the signal is transmitted through the plurality of conductive wires 11.

In the above-described conductive metal layer 21, a plurality of lines having a narrow width are electrically connected to each other on the third insulating film 17. For example, the conductive metal layer 21 is formed to have a mesh shape, whereby the portion of the third insulating film 17 where the conductive metal layer 21 is not formed is exposed. Therefore, the conductive metal layer 21 has a small area, whereby the resistance can be increased so that the impedance of the plurality of conductors 11 can be matched without using a separate dielectric film, thereby reducing the thickness of the cable. In addition, the flexibility can be improved, so it is easy to be folded and used in a narrow space inside the electronic device.

In the conductive metal layer 21, a conductive metal such as aluminum, silver, gold, copper, nickel, molybdenum, nickel or tin is deposited by vacuum evaporation, chemical vapor deposition (CVD) or physical vapor deposition (PVD). It may be formed by a method or plating. The conductive metal layer 21 may be formed by forming a release layer on the third insulating film 17 to expose a portion where a conductive wire is to be formed, and removing the release layer after depositing or plating the exposed portion. have. In addition, the conductive metal layer 21 may be formed by depositing or plating the conductive metal on the third insulating film 17 and patterning by a photolithography method.

In addition, the conductive metal layer 21 may be formed by bonding a foil of a conductive metal such as aluminum, silver, gold, copper, nickel, molybdenum, nickel, or tin. When the conductive metal layer 21 is formed of the foil of the conductive metal, the conductive metal layer 21 may be formed by attaching the foil of the conductive metal on the third insulating film 17 and patterning the photolithography method.

In the above, the line width of the conductive metal layer 21 is determined by the length, line width, thickness, and pitch of the plurality of conductive wires 11, and the line width of the conductive metal layer 21 may be formed in a size of 0.1 mm to 5 mm. .

In the case where the conductive metal layer 21 is formed by a deposition or plating method, a polyurethane-based resin, a polyester-based resin, or an acrylic to facilitate deposition or plating between the third insulating film 17 A primer layer coated with a synthetic resin such as an (acryl) resin and a vinyl resin may be formed.

Like the first and second insulating films 13 and 15, the fourth insulating film 23 may be made of nylon, polyimide, polyvinylacetate, polyurethane, and polyester ( It is formed on the conductive metal layer 21 to a thickness of about 5 ~ 400㎛ with a synthetic resin such as polyester, polyethylene (polyethylene) or polypropylene (polypropylene). In the above, the fourth insulating film 23 is formed to be shorter than the length of the second insulating film 15 so that both ends of the conductive metal layer 21 are exposed in the longitudinal direction. The portion exposed without being covered by the fourth insulating film 23 at both ends of the conductive metal layer 21 becomes the ground part 27.

In the above, the conductive metal layer 21 is formed on the third insulating film 17, and the fourth insulating film 23 is bonded onto the third insulating film 17 on which the conductive metal layer 21 is formed. A lower portion of the third insulating film 17 in which the 21 and fourth insulating films 23 are sequentially stacked is attached to the second insulating film 15 to form a flexible flat cable.

In the above-described flexible flat cable, the conductive metal layer 21 for shielding electromagnetic waves is formed such that a plurality of lines having a narrow width, such as a mesh shape, are electrically connected to each other. Accordingly, since the conductive metal layer 21 is not formed on the entire surface of the third insulating film 17, the conductive metal layer 21 has a small area and the resistance increases. Therefore, the impedance of the plurality of conductors 11 can be matched without using a separate dielectric film, so that the thickness of the cable can be reduced as well as the flexibility can be improved. It is easy.

In the flexible flat cable according to the embodiment of the present invention, both sides of the conductive metal layer are exposed without being covered by the fourth insulating film to be used as a grounding part. The conductive metal layer is formed on the third insulating film, and the fourth insulating film is Although described as being stacked, in another embodiment of the present invention, when both sides of the conductive metal layer are not exposed, the conductive metal layer is formed under the third insulating film so that the fourth insulating film is not required.

As described above, the present invention is merely an embodiment, and the present invention is not limited to the above-described embodiments, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. .

11: Lead wire 13, 15: 1st and 2nd insulating film
17: third insulating film 21: conductive metal layer
23: fourth insulating film 27: ground portion

Claims (8)

A first insulating film,
A plurality of conductive wires formed of a thin film of a conductive metal arranged at regular intervals so as not to be in contact with each other on the first insulating film;
A second insulating film bonded to the plurality of conductive wires on the first insulating film, the second insulating film being shorter than the length of the plurality of conductive wires to expose both ends;
A third insulating film bonded to the second insulating film,
A conductive metal layer shielding electromagnetic waves by forming a plurality of lines having a narrow width on the surface of the third insulating film to be electrically connected to each other;
A flexible flat cable comprising a fourth insulating film formed shorter than the length of the third insulating film to cover the conductive metal layer so that both ends thereof are exposed in the longitudinal direction to define a grounding part.
The flexible flat cable of claim 1, wherein the plurality of conductors are formed by any one of deposition, plating, and metal foil.
The flexible flat cable of claim 1, wherein the first to fourth insulating films are made of synthetic resin of nylon, polyimide, and propylene.
The flexible flat cable of claim 1, wherein the conductive metal layer is formed by depositing or plating conductive metal.
The flexible flat cable of claim 4, wherein the conductive metal layer is formed by forming a release layer to expose a portion of the conductive layer on the third insulating film, and depositing or plating the exposed portion, and then removing the release layer.
5. The flexible flat cable of claim 4, wherein the conductive metal layer is formed by depositing or plating a conductive metal on the third insulating film and patterning the same by a photolithography method.
The flexible flat cable of claim 1, wherein the conductive metal layer is formed by attaching a foil of a conductive metal on the third insulating film and patterning the photo by a photolithography method.
A first insulating film,
A plurality of conductive wires formed of a thin film of a conductive metal arranged at regular intervals so as not to be in contact with each other on the first insulating film;
A second insulating film bonded to the plurality of conductive wires on the first insulating film, the second insulating film being shorter than the length of the plurality of conductive wires to expose both ends;
A conductive metal layer shielding electromagnetic waves by forming a plurality of lines having a narrow width on the surface of the second insulating film to be electrically connected to each other;
A flexible flat cable comprising a third insulating film to cover the conductive metal layer on the second insulating film.

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