Cable with a carbonized insulator and method for producing such a cable

Abstract

A cable is specified, specifically for a signal line, which extends in a longitudinal direction and which includes an inner conductor and also an outer conductor. Between the inner conductor and the outer conductor there is formed an insulating material which surrounds the inner conductor and which has a surface that has been at least partially carbonized. Furthermore, a production method for such a line is specified.

Claims

1. A cable, comprising: an inner conductor and an outer conductor extending in a longitudinal direction of the cable; and an insulating material disposed between said inner conductor and said outer conductor, and surrounding said inner conductor, said insulating material having a surface that is partially carbonized at least intermittently, and wherein a structure is formed on said surface.

2. The cable according to claim 1, wherein said surface of said insulating material has the characteristics of having been carbonized by laser irradiation.

3. The cable according to claim 2, wherein a carbonization of said surface is formed by infrared laser radiation.

4. The cable according to claim 1, wherein said surface is completely carbonized at least in segments thereof.

5. A method for producing a cable, comprising: surrounding an inner conductor with an insulating material; partially carbonizing a surface of the insulating material at least intermittently, and forming a structure on the surface; and surrounding the insulating material with an outer conductor.

6. The cable according to claim 1, wherein said structure is a conductive structure.

7. The cable according to claim 1, comprising a first longitudinal portion, along which said surface of said insulating material has been completely carbonized, and a second longitudinal portion, along which said surface of said insulating structure has been merely partially carbonized and formed with said structure.

8. The cable according to claim 1, wherein said structure is a filter structure.

9. The cable according to claim 1, wherein said structure has been formed periodically in the longitudinal direction.

10. The cable according to claim 1, wherein said structure is formed with a plurality of transverse tracks which extend at right angles to the longitudinal direction.

11. The cable according to claim 1, wherein said structure extends in meandering path in the longitudinal direction.

12. The cable according to claim 1, wherein said structure is formed with a principal track, proceeding from which a multiplicity of transverse ribs extend at right angles to the longitudinal direction.

13. The cable according to claim 12, wherein said principal track is one of at least two principal tracks each having been formed with a multiplicity of transverse ribs which are arranged alternately in the longitudinal direction and engage one another.

14. The cable according to claim 1, which comprises a further insulating material applied over said insulating material and embedding said at least partially carbonized surface and forming an insulation with an embedded carbonized layer.

15. The cable according to claim 1, formed as a coaxial cable wherein said insulating material serves as a dielectric.

16. The cable according to claim 1, formed as a shielded core wherein said insulating material is a core sheath and said outer conductor is a shielding.

17. The cable according to claim 1, formed as a signal conducting line.

18. The method according to claim 5, which comprises carbonizing the surface with a laser.

19. The method according to claim 18, which comprises carbonizing the surface with an infrared laser.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a cross-sectional view of the cable according to the invention;

(2) FIG. 2 is an illustration of a production method for the cable;

(3) FIG. 3 is a partial developed view of a filter structure for the line; and

(4) FIG. 4 is a side view of a variant of the cable.

DETAILED DESCRIPTION OF THE INVENTION

(5) Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a cable 2 in a cross-section with respect to the longitudinal direction R thereof. The cable 2 has an inner conductor 4 which, for instance, is solid or a stranded conductor. The inner conductor 4 is surrounded by an insulating material 6. This material forms a sheath or rigid sheath for the inner conductor 4. The insulating material 6 has a surface 8 which faces outward with respect to the inner conductor 4. Furthermore, an outer conductor 10 is arranged around the inner conductor 4 and the insulating material 6. In a variant, the cable 2 is a shielded core. The outer conductor 10 then takes the form of a shielding. In another variant, the cable 2 is a coaxial cable. The outer conductor 10 then takes the form of a foil conductor, for example; the insulating material 6 serves as dielectric. Here, in addition, an outer sheath 12 is arranged around the aforementioned components. In variants that are not shown, yet further sheaths, conductors, layers or similar are arranged. In a preferred but non-illustrated variant, additional insulating material 6 is arranged between the outer conductor 10 and the insulating material 6, so that the surface 8 does not abut the outer conductor 10 but rather is embedded in an insulation 14 of the inner conductor 4. Also in the variant shown in FIG. 1, the insulating material 6 forms an insulation 14 of the inner conductor 4.

(6) For the purpose of improving the electrical properties, in particular for the purpose of diminishing electrical interference effects, the surface 8 has been at least partially carbonized. This is effected as illustrated in FIG. 2, for instance. A method for producing the cable 2 is shown therein. In this case, the inner conductor 4 is supplied to an extrusion plant 16, by means of which the insulating material 6 is extruded onto the inner conductor 4, i.e., the inner conductor is sheathed, that is, surrounded, with insulating material 6. Subsequently the sheathed inner conductor 4 undergoes aftertreatment with a laser 18. In this process, laser radiation L is applied onto the surface 8, and the latter is thereby carbonized. The insulating material 6 burns, in the course of which conductive particles consisting of carbon are produced. In order to prohibit volatilization of the carbon by reaction with atmospheric oxygen, the carbonization is effected in a protective atmosphere S within a tube 20, through which the sheathed inner conductor 4 is guided. The laser 18 here is an infrared laser, which is particularly suitable for carbonizing the insulating material 6.

(7) In FIG. 2 the surface 8 is carbonized completely. The resulting cable 2 is then particularly low in microphonic noise. However, particularly in the case where use is made of a laser 18 for the purpose of carbonization, a structure 22 can also be formedthat is to say, the surface 8 is merely partially carbonized. As a result, the electrical properties of the cable 2 can be optimized. This is particularly advantageous in the case of a coaxial cable that is used for the transmission of signals at high frequencies, for instance above 100 kHz, especially above 1 GHz. The structure 22 can then be formed as a filter structure and filters out particular interference signalsthat is to say, it attenuates themso that the transmission properties of the cable 2 have been distinctly improved.

(8) A merely exemplary structure 22 is illustrated in FIG. 3. The representation in this case is such that the surface 8 has been cut open and unwound in the longitudinal direction R, in order to enable a complete representation in the plane. The structure 22 which is shown then extends around the insulating material in such a manner that the upper edge and lower edge of the structure 22 adjoin one another.

(9) The structure 22 shown in FIG. 3 exhibits several, here three, principal tracks 24, one of which extends in meandering manner, here in the manner of a square-wave signal. The meandering principal track 24 in this case exhibits transverse tracks 26 which extend perpendicularly with respect to the longitudinal direction R and are connected amongst themselves so as to form the rectangular shape. The transverse tracks 26 are arranged at varying spacings A from one another. In a variant, the structure 22 has been formed in such a manner that the two principal tracks 24 extending in straight lines abut one another directly on the upper and lower edges of the structure 22 and jointly form a principal track 24.

(10) Proceeding from the principal tracks 24, in each instance a large number of transverse ribs 28 have been formed which, like the transverse tracks 26, extend perpendicularly with respect to the longitudinal direction R and thereby form a ramification of the principal tracks 24. The transverse ribs 28 of the various principal tracks 24 engage one another, so that a comb structure has been formed. The transverse ribs 28 here are equally spaced from one another in each instance; however, this is not mandatory.

(11) The entire structure 22 in the present case is also periodic and consists of similar portions with a period P, which are arranged in series in the longitudinal direction R.

(12) In FIG. 4 a variant of the cable 2 is shown which includes a first longitudinal portion 30, along which the surface 8 of the insulating material 6 has been completely carbonized, and a second longitudinal portion 32, along which the surface 8 of the insulating structure 6 has been merely partially carbonized and formed with a structure 22. The longitudinal portions 30, 32 have been formed in series in the longitudinal direction R. This cable 2 is particularly suitable as a sensor, since the differing line portions 30, 32 react differently to interferences, as a result of which such interferences can be localized.