Foil conductor

State of the art

The invention relates to a conductor foil with the features specified in the preamble of claim 1.

Conductor foils made of an elastically deformable, non-conductive carrier foil strip with conductor tracks that run in the longitudinal direction of the carrier foil strip and are insulated from the outside are used, for example, in motor vehicles in order to connect various electrical / electronic components to one another. The conductor foils consist of a carrier foil made of, for example, polyimide, onto which thin conductor tracks made of copper are applied, which are covered with an insulating material, for example a further insulating foil or an insulating varnish. Contacting devices can be arranged at the ends of the band-shaped conductor film, which are often designed as soldering eyes and are soldered with plug pins of electrical or electronic assemblies. Such conductor foils are known for example from DE 197 19 238 C1. The conductor foils are elastically deformable and therefore relatively insensitive to vibrations and shaking loads.

However, it is disadvantageous that the known conductor foils are limp, so that it is not possible to give the conductor foils a permanent two- or three-dimensional shape by manual or mechanical bending. This disadvantage complicates the assembly of the conductor foil in electrical devices, since the flexible conductor foil has to be held steadily during the assembly and, if necessary, fasteners are necessary to fix the conductor foil to housing walls or holding frames of electrical devices.

Advantages of the invention

This disadvantage is avoided by the conductor foil according to the invention with the characterizing features of claim 1. The conductor film advantageously has at least one permanently deformable shaping element which is applied to a carrier film strip of the conductor film and is insulated from the conductor tracks and extends in the longitudinal direction of the carrier film strip. The shaping element can be arranged on the carrier film in a simple and inexpensive manner and advantageously makes it possible to give the conductor film a permanent two- or three-dimensional shape. Under<img file="EP1041584A2_D0001.tif" />permanently "is to be understood here that the two- or three-dimensional shape of the conductor foil does not change by itself during transport or assembly, but can nevertheless be changed again by bending the shaping element again manually or mechanically. It is particularly advantageous that the The bending stiffness of the conductor foil resulting from the shaping element greatly simplifies the manual and mechanical processing of the conductor foils. The known manufacturing process of the conductor foils advantageously has to be changed only slightly. Since the shaping element runs in the longitudinal direction of the carrier film strip in the same direction as the conductor tracks, the conductor film can advantageously be rolled up in the longitudinal direction. Depending on requirements, pieces of different lengths can then be cut from the roll and further processed. When rolling up or unrolling, a certain resistance has to be overcome, which results from the fact that the shaping element is curved or stretched, but this is quite acceptable in view of the advantages described above.

Advantageous exemplary embodiments and further developments of the invention are contained in the features of the subclaims.

It is particularly simple to manufacture the at least one shaping element from metal. For example, the shaping element can be a single metal wire running in the longitudinal direction of the carrier foil strip, which is introduced as an insert into the conductor foil or glued to the carrier foil strip, which makes the production of the conductor foil only somewhat more complex. The metal wire can be made of very inexpensive material and increases the manufacturing costs of the conductor foil only slightly. By manual or mechanical bending of the metal wire arranged in the conductor foil, the conductor foil can be brought into a permanent shape in a very simple manner and the assembly of the conductor foil, for example in the device housing of an electronic control device, can be greatly facilitated. Two metal wires running parallel to one another in the longitudinal direction of the carrier film strip can advantageously be arranged on the conductor film. This makes it particularly easy to give the conductor foil a three-dimensional shape.

However, the shaping element can also be a metal foil applied to the carrier foil strip, the thickness of which is sufficiently large to enable the conductor foil to be deformed permanently.

drawings

Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the description below. It shows<ul id="ul0001" list-style="none" compact="compact"><li>1 shows a cross section through a first embodiment of a conductor foil according to the invention,</li><li>2 shows a plan view of the conductor foil from FIG. 1,</li><li>3 to 6 show further exemplary embodiments of the conductor foil according to the invention,</li><li>7 is a perspective view of a conductor foil according to the invention bent into a two-dimensional shape,</li><li>8 is a perspective view of a conductor foil according to the invention bent into a three-dimensional shape.</li></ul>

Description of the embodiments

1 and 2 show a first exemplary embodiment of the conductor foil according to the invention. The conductor film 1 comprises a carrier film tape 2 made of an electrically insulating and elastically deformable material, such as polyimide. Conductor tracks 3 are produced on the carrier film strip 2 and run essentially parallel to one another in the longitudinal direction of the carrier film strip 2. The conductor tracks 3 are made of copper with a thickness of, for example, 40 μm or less in a manner known per se. In this process, copper is first deposited in a structured photo process on the carrier film strip and then galvanically reinforced. The thinner the copper structures, the cheaper the conductor foil can be manufactured. As can also be seen in FIG. 1, the conductor tracks 3 are covered by a protective coating or an insulation layer 5 insulated from the outside. This can be, for example, another insulating film, a suitable top coat or an insulating spray. FIG. 2 shows a plan view of a section of the carrier film strip 2 from FIG. 1. In addition to the conductor tracks 3, a shaping element 4 running parallel to the conductor tracks in the longitudinal direction of the carrier film strip is applied to the carrier film strip 2, which in this exemplary embodiment is designed as a metal wire with a circular cross section running in the middle of the conductor film. The metal wire 4 is insulated from the conductor tracks 3 by the insulation layer 5 and can be, for example, an inexpensive copper wire with a diameter of one millimeter. The diameter of the metal wire should be at least large enough that permanent deformation of the conductor foil 1 can be achieved by bending the wire. However, other materials and configurations of the shaping element 4 are also conceivable. Since the at least one shaping element 4, unlike the conductor tracks 3, does not have to be designed as an electrical conductor, it is also possible, for example, to manufacture the shaping element 4 from a plastically deformable plastic. FIG. 7 shows the conductor foil 1 from FIG. 1 after the conductor foil 1 has been bent into a desired two-dimensional shape. This shape can be adapted, for example, to a specific housing contour of an electrical device. By means of the metal wire 4, the conductor foil 1 maintains this shape permanently, which facilitates the assembly of the conductor foil 1 in the electrical device in places that are difficult to access. The ends of the conductor foil 1 in FIG. 7 can be provided with soldering eyes or other contacting means, not shown.

3 shows a further exemplary embodiment of the conductor foil 1 according to the invention. In contrast to FIG. 1, the shaping element is here on the side of the carrier foil strip 2 opposite the conductor tracks 3_- an adhesive 8 glued to the carrier tape. The shaping element 4 here has an approximately semicircular cross section.

4 shows an exemplary embodiment in which the conductor tracks 3 on the upper side of the carrier foil strip 2 are insulated from the outside by a further polyimide layer 6. On the underside of the carrier film strip 2, two metal wires 4 are arranged at a distance from one another via an elastically deformable further insulating layer 7, which can also be designed as a polyimide layer. The two metal wires 4 in particular facilitate a three-dimensional shaping of the conductor foil 1, as is shown by way of example in FIG. 8.

FIG. 5 shows an exemplary embodiment in which the shaping element 4 is formed by a metal layer 4 with a thickness of 100 μm, which is applied to the underside of the carrier film strip 2 via an adhesive layer 10. The metal layer 4 achieves a plastic deformability of the conductor foil 2 about two mutually perpendicular axes running in the plane of the carrier foil 2.

6 shows a further exemplary embodiment in which the shaping element 4 is arranged on the upper side of the carrier foil strip 2 next to the conductor tracks 3 and is covered by an insulating polyimide layer 6. In this exemplary embodiment, the shaping element 4 extending in the longitudinal direction of the carrier film strip 2 has a trapezoidal cross section.

In addition, further configurations and arrangements are possible, the shaping element, as shown in FIG. 1, either being completely embedded in insulating material or, as in FIG. 5, not being covered on one side with insulating material.