OPTICAL-ELECTRICAL CONDUCTOR ASSEMBLY COMPRISING AN OPTICAL WAVEGUIDE AND AN ELECTRICALLY CONDUCTIVE LAYER

Abstract

An optical-electrical conductor assembly is provided that includes an optical waveguide that has an outer organic jacket layer and a functional layer system disposed on the outer jacket layer of the optical waveguide. The functional later has a base layer portion with a single layer or a sequence of layers and an electrically conductive layer disposed on the base layer portion. The electrically conductive layer has a single layer or a sequence of layers.

Claims

1. An optical-electrical conductor assembly, comprising: an optical waveguide having an outer organic jacket layer; and a functional layer system located on the outer organic jacket layer, the functional layer system comprises a base layer portion and an electrically conductive layer, the base layer portion consists of a single layer or a sequence of layers, the electrically conductive layer consists of a single layer or a sequence of layers.

2. The assembly of claim 1, further comprising an optically conductive core having a refractive index that is greater than a refractive index of the outer organic jacket layer.

3. The assembly of claim 1, further comprises a cladding surrounding the core, the cladding being disposed between the core and the outer organic jacket layer.

4. The assembly of claim 3, further comprising an optically conductive core having a refractive index that is greater than a refractive index of the cladding.

5. The assembly of claim 1, wherein the outer organic jacket layer comprises a material selected from a group consisting of polyamide (PA), polyimide (PI), polymethyl methacrylate (PMMA), wax, wax-like constituents, and alkylsilane.

6. The assembly of claim 1, wherein the base layer portion comprises a layer or sequence of layers disposed on the outer organic jacket layer, wherein the layer comprises a material selected from a group consisting of an oxide, a boride, carbide, nitride, oxynitride, carbonitride, and a metal.

7. The assembly of claim 6, wherein the oxide is selected from a group consisting of SiO.sub.2, TiO.sub.2, Al.sub.2O.sub.3, SnO.sub.2, and HfO.sub.2, or wherein the metal is selected from a group consisting of Si, Ti, Mo, and Cr.

8. The assembly of claim 1, wherein the base layer portion comprises a near-surface zone of the outer organic jacket layer, the near-surface zone having a property selected from a group consisting of an altered surface property, an altered surface energy, an increased number of oxygen radicals, a chemically altered surface property, and a physically altered surface property.

9. The assembly of claim 1, wherein the base layer portion has a thickness between 5 nm and 3000 nm and/or wherein the electrically conductive layer has a thickness between 5 nm and 6000 nm and/or wherein the electrically conductive layer has a sheet resistance between 0.01 and 1000 ohms/sq.

10. The assembly of claim 1, wherein the base layer portion and the electrically conductive layer have an adhesion therebetween that is greater than an adhesion between the outer organic jacket layer and another electrically conductive layer disposed thereon.

11. The assembly of claim 1, wherein the base layer portion has at least one layer configured to inhibit diffusion of oxygen and/or to inhibit ions from acidic or alkaline solutions into the electrically conductive layer.

12. The assembly of claim 1, wherein the base layer portion has a thermal expansion coefficient that is between a thermal expansion coefficient of the outer organic jacket layer and a thermal expansion coefficient of the electrically conductive layer.

13. The assembly of claim 1, wherein the base layer portion comprises the sequence of layers that have a respective coefficient of thermal expansion which increases or decreases according to the sequence of layers.

14. The assembly of claim 1, wherein the electrically conductive layer further comprises another layer disposed on the base layer portion, the another layer comprises a substance selected from a group consisting of titanium, silicon, aluminum, gold, silver, molybdenum, tungsten, zirconium, and an alloy thereof with an element selected from a group consisting of Ni, Zn, Y, Sn, and Ge.

15. The assembly of claim 1, wherein the functional layer system comprises a barrier layer disposed on the electrically conductive layer, wherein the barrier layer consists of a single layer or a sequence of layers, and wherein the barrier layer is configured to inhibit diffusion of oxygen and/or inhibit diffusion ions from acidic or alkaline solutions into the electrically conductive layer.

16. The assembly of claim 15, wherein the barrier layer has at least one layer with a hardness of at least 800 HV in compliance with the DIN EN ISO 145774:2007-8 test standard.

17. The assembly of claim 15, wherein the barrier layer comprises a layer disposed on the electrically conductive layer, wherein the barrier layer comprises a material selected from a group consisting of a nitride, an oxide, a carbide, boride, oxynitride, carbonitride, and a ternary system thereof, wherein the nitride is selected from a group consisting of Si.sub.3N.sub.4, BN, AlN, TiN, AlSiN, SiON, SiAlON, and any alloy thereof, wherein the oxide is selected from a group consisting of Si, Al, Ti, Zr, Zn, Sn, Ta, Nb, Y, TiO.sub.2, and SiO.sub.2,

18. The assembly of claim 1, wherein the assembly is configured for a use selected from a group consisting of a dental treatment device, a tissue treatment device, a tissue stimulation device, a container level monitoring device, and a bioreactor level monitoring device.

19. A method for producing an optical-electrical conductor assembly, comprising: providing an optical waveguide that has an outer jacket layer and coating the jacket layer with a functional layer system, wherein the step of coating the jacket layer with a functional layer system comprises producing a base layer portion and depositing an electrically conductive layer on the base layer portion, wherein the base layer portion consists of a single layer or a sequence of layers, and wherein the electrically conductive layer consists of a single layer or a sequence of layers.

Description

BRIEF DESCRIPTION OF FIGURES

[0045] FIG. 1 is a cross-sectional view through an optical-electrical conductor assembly; and

[0046] FIG. 2 is a cross-sectional view through another optical-electrical conductor assembly.

DETAILED DESCRIPTION

[0047] FIG. 1 shows an optical-electrical conductor assembly 1 comprising an optical waveguide 10. Optical waveguide 10 has a core 11 made of fused silica and a cladding 12 also made of fused silica here. The refractive index n1 of the core 11 is greater than the refractive index n2 of the cladding 12. In addition, and in particular as a mechanical protection, a jacket layer 13 (buffer) is provided in the form of a polymer layer or polymer jacket. As is common for such optical waveguides, the jacket layer 13 comprises polyimide, PMMA, or polyamide, or is made of at least one of these materials.

[0048] On the jacket layer 13, the optical-electrical conductor assembly 1 has a functional layer system 20 consisting, in this example, of a base layer portion 21 in the form of an adhesion promoting layer directly on the jacket layer 13, a conductive layer 22, and an outer barrier layer (passivation layer) 23. The functional layer system 20 on the outer jacket layer 13 can be produced by cathode sputter deposition or another vacuum deposition process (e.g. vapor deposition).

[0049] FIG. 2 shows an optical-electrical conductor assembly 1 comprising an optical waveguide 10, and in this case the optical waveguide 10 comprises a core 11 and a jacket layer 13 directly surrounding the core 11. In this case, the refractive index n1 of the core 11 is slightly greater than the refractive index n2 of the jacket layer 13. The jacket layer 13 thus provides for total internal reflection at the interface with the core 11 and thus for the conduction of light. At the same time, the jacket layer 13 may serve as a mechanical protective layer.

[0050] The optical-electrical conductor assembly 1 furthermore comprises a functional layer system 20 which may be designed and produced in the same way as in FIG. 1.

[0051] As mentioned above, the functional layer system 20 may comprise a plurality of individual layers which, in the present case, comprise a base layer portion 21 in the form of an adhesion promoting layer, the actual conductive layer 22, and an optional barrier layer (passivation layer) 23. With regard to the manufacturing of such an optical-electrical conductor assembly, the entire layer sequence can be deposited in a single batch cycle without interrupting the vacuum process, which also allows to cost-effectively coat in parallel a plurality of components that include such optical-electrical conductor assemblies 1.

[0052] Further exemplary embodiments for producing an optical-electrical conductor assembly are described below.

Example 1

[0053] Optical-electrical conductor assembly 1 comprising an optical waveguide 10 in the form of a fused silica fiber having a core 11 with a diameter of 150 μm, a cladding 12 with a diameter of 180 μm, and a jacket layer 13 in the form of a polymer layer made of polyimide, with an outer diameter of the optical waveguide 10 of approximately 210 μm in total.

[0054] A base layer portion was produced by subjecting the jacket layer to a pretreatment. Here, ultrasonic cleaning with an alkaline cleaning agent, a neutral cleansing agent, and IR drying were employed.

[0055] A conductive layer was deposited, consisting of a titanium coating with a thickness of 15 nm, which was produced by DC magnetron sputter deposition. Coating was performed in vacuum at a processing pressure of less than 1 E-2 mbar. The sputter target was chosen to have a purity of 99%. The minimum distance between substrate and target was chosen to be 5 cm, with the optical waveguide protruding into the plasma.

[0056] A 4-point measuring device was used to determine the sheet resistance, for which a value of 10 ohms/sq was measured (the unit ohms/sq corresponds to the unit ohm). This corresponds to a specific resistance of 1.5 E-5 ohm.Math.cm. The adhesion of the layer system was verified using an adhesion test in compliance with DIN 58196-6(1995-07). No detachment of the functional layer system from the optical waveguide was found.

Example 2

[0057] An optical waveguide in the form of a quartz fiber with a jacket layer made of polyimide was cleaned and pre-activated by an atmospheric plasma in the form of a corona discharge. Then, a silicon oxide coating was deposited using a reactive medium-frequency plasma, which was provided with a conductive molybdenum coating with a layer thickness of 24 nm without vacuum break. This layer was then passivated with a silicon nitride coating with a layer thickness of 100 nm by reactive magnetron sputter deposition, without breaking the vacuum.

[0058] In a subsequent sheet resistance test, a sheet resistance of 5 ohms/sq was determined by an inductive measuring technique using an eddy current measuring device. According to the aforementioned adhesion test, no delamination was found.

Example 3

[0059] An optical waveguide in the form of a fused silica fiber with a jacket layer made of polyimide is cleaned by ultrasonic cleaning according to Example 1. The conductive layer disposed directly on the jacket layer comprises molybdenum with a sheet resistance of 10 ohms/sq. To protect the molybdenum coating, a barrier coating made of TiO.sub.2 is optionally coated thereon. Both coatings are produced in a magnetron sputter deposition process in vacuum, with the optical waveguides protruding into the plasma so that a nearly homogeneous coating is created. In the case of the molybdenum coating, the coatings are made from a metallic sputter deposition target of purity 3N, in the case of the TiO.sub.2 coating from a metallic target or a partially ceramic target while adding oxygen. In this case, the TiO.sub.2 coating is partially amorphous and partially anatase. In a subsequent mechanical load test in which aluminum test specimens with a mass of 22.5 g are pulled over the length of the optical waveguide, no scratches or delamination of the metallic coating are found in light microscopic images of up to 100 times magnification.

Example 4

[0060] In a further exemplary embodiment, an optical waveguide in the form of a fused silica fiber and having a jacket layer made of polyimide is pretreated by wet-chemical cleaning. This is followed by the deposition of layers of both the base layer portion and the conductive layer while adding oxygen and argon. In order to ensure improved adhesion between the jacket layer and the conductive layer, an adhesion promoting layer made of TiO.sub.2 is formed therebetween, and the ratio of oxygen to the total flow of oxygen and argon is less than 0.4 for producing it. Subsequently, a metallic titanium coating with a sheet resistance of 1 ohms/sq is deposited as a conductive coating, and the ratio of oxygen to the total flow of oxygen and argon is less than 0.1 for producing it. A further TiO.sub.2 coating is deposited as an additional passivation, and the ratio of oxygen to the total flow of oxygen and argon is less than 0.7 for producing it.

[0061] The ratio of oxygen to the total flow (see the aforementioned exemplary ratios) indicates how close the result will be to a metal character or a dielectric character of the TiO.sub.2 layer.

[0062] It will be apparent to a person skilled in the art that the embodiments described above are to be understood as examples and that the invention is not limited thereto, but rather can be varied in multiple ways without departing from the scope of the claims. Furthermore, the features of the optical-electrical conductor assembly are disclosed in a corresponding manner as features for the method for producing an optical-electrical conductor assembly and vice versa. Features, regardless of whether they are disclosed in the description, the claims, the figures, or otherwise, also individually define components of the invention, even if they are described together with other features.

LIST OF REFERENCE NUMERALS

[0063] 1 Optical-electrical conductor assembly [0064] 10 Optical waveguide [0065] 11 Optically conductive core [0066] 12 Cladding [0067] 13 Organic jacket layer [0068] 20 Functional layer system [0069] 21 Base layer portion [0070] 22 Conductive layer [0071] 23 Barrier layer