Patent Application
20210085956
This Utility Patent Application claims priority to German Application No. 10 2019 006 709.6 filed on Sep. 25, 2019, which is incorporated herein by reference.
One aspect relates to a method for the electrical connection of an electrode to a conductor to form an electrode-conductor composite, an electrode-conductor composite produced according to the method according to one embodiment, and the use of laser irradiation of a metalliferous layer for producing an electrode-conductor composite. An electrode-conductor composite of this type is in particular advantageous for the use in the medical technology.
The electrical contact-connection of an electrical conductor can often represent a large challenge, in particular in the case of small dimensions. Good electrical conductivity and mechanical stability, e.g., are thereby desired even in the case of heavy use for a longer period of time. This applies in particular in the case of the electrical contact-connection of lines in medical devices. In devices, which are inserted into the human or animal body, it is desirable to use thin lines, which, however, may represent a challenge for the electrical contact-connection due to their size.
Special emphasis is placed on the reliability of medical devices, such as, e.g., pacemakers, implantable cardioverters, defibrillators, and cardiac resynchronization devices, in particular on the lowest possible material fatigue. In particular the lines and the electrical connections are exposed to high loads during operation. Due to the fact that invasive surgery is usually required to insert medical devices into the body or to remove or to replace parts thereof, a long service life of the individual components of the device is desirable in order to reduce the need for surgical procedures.
Electrical contact-connections, which are located on a flexible substrate, represent particular challenges, for example in the case of the contact-connection of conductor tracks with sensors or stimulation electrodes, which are located on flexible plastic substrates. Further difficulties also result, for example, when flexible electrodes are very thin and the leads, which connect the electrodes to the pulse generators, are dimensioned significantly larger. In many cases, the different materials in the area of the contact-connection (metal and polymers) furthermore represent a large challenge.
The contact-connection is often formed too rigidly in the prior art, so that the advantage of the flexibility gets lost. Known contact-connections are furthermore not sufficiently stable in the long term, so that the service life is not sufficiently long (fatigue breakage at the contact-connection).
It is a further disadvantage of existing contact-connections that an additional material, which is not biocompatible, is often required for the connection of the different components. These non-biocompatible materials, however, may be problematic for the use in medical devices.
In response to the bonding, as described, for example, in US20180126155A1, a contact-connection can take place without additional material. The formed contact-connection, however, is not stable in the long term and is also not suitable for all materials. The adhesion, as described, for example, in EP0612538A2, provides for a flexible connection, but an additional material is required thereby, which is generally not biocompatible and often becomes brittle after a certain period of time. Welding provides for a contact-connection without additional material, but forms a rigid, relatively large-volume contact-connection. In many cases, the welding of thin layers is demanding or impossible, because they can be thermally destroyed, in particular while attempting the contact-connection with high-melting materials, such as platinum. The soldering can be performed as welding at low temperature, but the formed contact-connections are likewise rigid, and a non-biocompatible, additional material is required.
For these and other reasons there is a need for the present embodiment.
It is the object of one embodiment to solve the above-described and further problems of the prior art. One embodiment provides, for example, for a contact-connection, which is stable in the long term, with flat construction in particular on flexible substrates, so that the flexibility of the entire system of lead and flexible electrode is ensured. This method can be adapted more easily to required design variations than prior art methods and provides products with improved properties, as described below. The improved contact-connection can illustrate itself, for example, in a higher reliability, stability, and conductivity. One embodiment provides, for example, a contact-connection with improved breaking strength and breaking stability.
These objects are solved by using the methods and devices described herein, in particular by using those, which are described in the patent claims.
Embodiments are described below.
The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.
In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is illustrated by way of illustration specific embodiments in which one embodiments may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present embodiments. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present embodiments are defined by the appended claims.
It is to be understood that the features of the various exemplary embodiments described herein may be combined with each other, unless specifically noted otherwise.
With regard to the embodiments described herein, the elements of which “have” or “comprise” a certain feature (e.g. a material), a further embodiment is generally always considered, in which the respective element consists only of the feature, i.e. does not include any further components. The word “comprise” or “comprising” is used synonymously with the word “have” or “having” herein.
When an element is identified with the singular form in an embodiment, an embodiment is likewise considered, in the case of which several of these elements are present. Unless otherwise specified or unambiguously ruled out from the context, it is generally possible and is hereby unambiguously considered that features of different embodiments can also be present in the other embodiments described herein. It is likewise generally considered that all features, which are described herein in connection with a method, are also applicable for the products and devices described herein. All of these considered combinations are not listed explicitly in all cases only for reasons of a shorter description. Technical solutions, which, as is well known, are equivalent to the features described herein, are to generally also be captured by the scope of the embodiments.
A first aspect of one embodiment relates to a method for the electrical connection of an electrode to a conductor to form an electrode-conductor composite, comprising
(i) bringing an electrode and/or a conductor into contact with a metalliferous layer,
(ii) irradiating the metalliferous layer with a laser, and
(iii) thus forming a coherent, electroconductive metal layer.
The metallic layer contains a metal or a metal oxide. Cu, Pt, Au, Ir, Pd, Ti, Ta, Fe, Nb, Ni, or alloys thereof, or further alloys, such as, for example, MP35N, are examples for suitable metals.
Platinum oxide, iridium oxide, titanium oxide, tantalum oxide, niobium oxide, copper oxide are examples for suitable metal oxides.
The metalliferous layer is preferably set up in one embodiment to form a coherent, electroconductive metal layer, when it is irradiated with a laser. For example particles of copper oxide, which are in a suspension, are converted into metallic copper by irradiating with a laser, so that an electroconductive coherent metal layer is formed on a substrate. Suitable copper oxide is, for example, the NanoArc copper oxide powder, which can be obtained from Alfa Aesar, with a particle dimeter of approximately 200-300 nm. This is described, for example, in Kang et al, J. Phys. Chem. C20111154823664-23670. For example infrared lasers with a wavelength of approximately 1000 nm, e.g. 1070 nm, are particularly suitable for the conversion of CuO into metallic copper. A pulse energy of 2 μJ, a pulse with of 50 ns, a pulse frequency of 300 kHz, and an irradiation surface of a diameter of 25 μm, was used thereby in the example described by Kang et al. It becomes evident to the person of skill in the art that other parameters, which can be determined in simple tests or which are known in the technical literary, are optionally advantageous for other materials. The values should always be selected so that the power of the laser is selected to provide for the formation of an electroconductive metal layer, without damaging the electrode, the conductor, or optionally the substrate.
In one embodiment, metal particles are fused to form a coherent electroconductive metal layer by irradiation with a laser. In one embodiment, metal particles and/or metal oxide particles are sintered to form a coherent electroconductive metal layer by irradiation with a laser.
The metalliferous layer can include a metal powder or a metalliferous suspension. In one embodiment, the metalliferous layer consists of a metal powder. In one embodiment, the metalliferous layer consists of a metalliferous suspension. A metalliferous suspension includes, for example, metal particles or metal oxide particles, and a liquid, for example water. This liquid can also include an organic solvent, for example a mixture of poly(vinylpyrrolidone) and ethylene glycol. The liquid can include a dispersing agent. A dispersing agent of this type is preferably selected in one embodiment so that it keeps the metal particles or metal oxide particles in the colloidal state in the liquid.
In one embodiment, the electrode and/or the conductor are located on a substrate. In one embodiment, the substrate is a film. In one embodiment, the substrate includes a plastic. In one embodiment, the substrate is flexible, for example a flexible plastic film. “Flexible” means that the substrate can be deformed significantly by manual force, without breaking or tearing, Examples for flexible substrates are plastic films, which are typically used as substrates for the production of film cables in the electronics industry. Polyester films with a thickness of 0.1-0.5 mm are examples for this. In one embodiment, the flexible substrate includes polyurethane, polyimide, silicon, PEEK, or LCP.
The suspension can be applied to the substrate by a coating process, for example spin coating.
“Coherent” means here that a metal layer is formed, which is formed continuously in such a way that it can serve as electrical connection of two electrical components.
A conductor is an electroconductive structure, which is provided for the electrical connection of electrical or electronic components. A conductor can be, for example, a wire, for example an electrically insulated wire, or a conductor track. The wire can be part of a cable.
The conductor can be, for example, a metal wire. In some embodiments, the conductor includes one or several of the metals Pt, Ir, Ta, Pd, Ti, Fe, Au, Ag, Mo, Nb, W, Ni, Ti, or a mixture or alloy thereof, respectively. In some embodiments, the conductor includes the alloys MP35, PtIr10, PtIr20, 316L, 301, or nitinol. The conductor can also include multi-layer material systems. In one embodiment, the conductor preferably includes MP35, Au, Ta, Pt, Ir, or Pd. In some embodiments, a part of the conductor consists of MP35, Au, Ta, Pt, Ir, or Pd, or alloys of these metals. In some embodiments, the conductor contains less than 3%, 2%, or less than 1% of Fe.
MP35 is a curable alloy on the basis of nickel-cobalt. A variation of MP35 is described in the industrial standard ASTM F562-13. In one embodiment, MP35 is an alloy, which includes 33 to 37% of Co, 19 to 21% of Cr, 9 to 11% of Mo, and 33 to 37% of Ni.
PtIr10 is an alloy of 88 to 92% of platinum and 8 to 12% of iridium.
PtIr20 is an alloy of 78 to 82% of platinum and 18 to 22% of iridium.
316L is an acid-resistant CrNiMo austenitic steel with approx. 17% of Cr; approx. 12% of Ni, and at least 2.0% of Mo. A variation of 316L is described in the industrial standard 10088-2. In one embodiment, 316L is an alloy, which includes 16.5 to 18.5% of Cr; 2 to 2.5% of Mo, and 10 to 13% of Ni.
301 is a chromium nickel steel with a high corrosion resistance. A variation of 301 is described in the industrial standard DIN 1.4310. In one embodiment, 301 is an alloy, which includes 16 to 18% of Cr and 6 to 8% of Ni.
Nitinol is a nickel-titanium alloy with shape memory with an orderly cubic crystal structure and a nickel portion of approximately 55%, wherein the remaining portion consists of titanium. Nitinol has good properties with respect to biocompatibility and corrosion resistance. Unless otherwise specified, all percentages herein are to be understood as percentage by mass (% by weight).
In one embodiment, the conductor has a spherical or a flattened form at its end. In one embodiment, the conductor is connected at this end to the metal layer. In one embodiment, the conductor is connected to the metal layer at this end by irradiation of a metalliferous layer with a laser.
An electrode is an electroconductive structure. In one embodiment, the electrode is suitable to output an electrical signal to the human body or to receive an electrical signal from the human body. An electrode can also include a conductor track. In one embodiment, the electrode is a conductor track, which is arranged on a substrate. In one embodiment, the conductor track is connected to a substrate. In one embodiment, the conductor track is connected directly to a substrate. In one embodiment, the electrode is a sensor or a stimulation electrode for use in the human or animal body. In one embodiment, the electrode includes a metal or a metal alloy, for example those metals or alloys, which are described herein as being suitable for the conductor. In one embodiment, the electrode consists of a biocompatible material. A biocompatible material is a material, which is suitable for the implementation into the human or animal body. In one embodiment, the electrode includes gold or platinum. In one embodiment, the electrode consists of gold or platinum.
In one embodiment, the electrode is set up to receive or to output an electrical signal. In one embodiment, the electrode is set up to receive an electrical signal from the human body or to output it to the human body. In some embodiments, the electrode includes one or several of the metals Pt, Ir, Ta, Pd, Ti, Fe, Au, Mo, Nb, W, Ni, Ti, or a mixture or alloy thereof, respectively. In some embodiments, the electrode includes the alloys MP35, PtIr20, PtIr10, PdIr10, 316L, or 301. The electrode can also include multi-layer material systems. In some embodiments, the electrode consists of one or several of these materials.
In one embodiment, the method includes the steps a to c:
In step a, an electrode and a conductor are provided, which are arranged on a substrate, for example a flexible plastic film. In one embodiment, the electrode and the conductor are preferably firmly connected to the substrate. In one embodiment, the electrode and the conductor are located on the same side of the substrate.
In step b, the electrode and the conductor are brought into contact with the metalliferous layer. For this purpose, a metalliferous layer can be applied to the substrate so that it simultaneously covers the electrode as well as the substrate at least partially. In one embodiment, the metalliferous layer is preferably applied at that location, at which the coherent metal layer is to be created, for example along the shortest connecting line between the electrode and the conductor.
The metalliferous layer can include, for example, a metalliferous suspension, a paste, or a metal power, or can consist thereof. The suspension, paste, or the powder can in each case include a metal and/or metal oxide. Metal or metal oxide particles are present in colloidal state in a suspension, i.e. they are dispersed evenly in a liquid. A paste is a suspension, which has a particle content, which is so high that it is no longer free-flowing. A powder is a granular medium, which includes only solid matter.
In step c, the metalliferous layer is irradiated with a laser, so that a coherent metal layer, which connects the electrode and the conductor in an electroconductive manner, is formed from the metal or metal oxide particles in the metalliferous layer. For example, metal oxide particles can thereby be reduced to form elemental metal, and/or metal particles can be fused or sintered to form a coherent layer.
In one embodiment, the method includes steps d to g:
A conductor is hereby initially provided on a substrate, as described above. In this step, however, an electrode does not necessarily also need to be provided yet. In a further step, the conductor is brought into contact with the metalliferous layer, as described above. The metalliferous layer can include, for example, a metalliferous suspension, a paste, or a metal powder, or can consist thereof, as described above. In a further step, an electrode is formed by irradiation of the metalliferous layer with a laser. In one embodiment, the formation of the electrode takes place by irradiation of the metalliferous layer with a laser in such a way that an electrical connection of the electrode to the conductor is formed directly. In one embodiment, the conductor and the electrode are connected to one another in a different way. An electrode-conductor composite is formed by the electroconductive connection of the electrode to the conductor.
In a further embodiment, an electrode is initially provided on the substrate by irradiation of a metalliferous layer with a laser, and a conductor is subsequently provided and is connected to the electrode. The conductor can thereby be formed by irradiation of a metalliferous layer with a laser or can be provided in a different way. This can take place, for example, with the help of complementary structures, as described in more detail below.
In some embodiment, the electrode and/or the conductor are fixed to the substrate, so that they do not change their position during the formation of the metalliferous layer. In one embodiment, the electrode and/or the conductor are embedded into the flexible substrate by irradiation with a laser. In one embodiment, the substrate is partially melted or softened at a suitable position by irradiation of the substrate, so that the electrode and/or the conductor sink into the substrate, and are thus embedded into the substrate. In one embodiment, the electrode and/or the conductor are pressed into the substrate. In one embodiment, the substrate is softened or melted by irradiation with a laser, and the electrode and/or the conductor are subsequently pressed into the softened or melted substrate. In one embodiment, the electrode and/or the conductor are preferably furthermore accessible to the outside, i.e. they can subsequently also be connected to one another in a conductive manner with the help of a metalliferous layer, without having to remove the substrate.
In one embodiment, the electrode and/or the conductor are fixed to the substrate by the embedding into the substrate, so that they are no longer movable relative to the substrate. The conductor and/or the electrode can, for example, be pressed or melted into the substrate.
In one embodiment, the electrode and/or the conductor are fixed to the substrate by applying an additional fixing layer. In one embodiment, the fixing layer is preferably arranged outside of the metalliferous layer and/or of the electrical connection formed therefrom. The contact-connection area between electrode and conductor can thus be kept free from the material of the fixing layer. This fixing layer can be, for example, an adhesive, a photoresist, or a low-melting plastic. In one embodiment, the low-melting plastic has a melting temperature of less than 300° C., 200° C., or 150° C. In one embodiment, the electrode and/or the conductor is fixed to the substrate by applying an additional fixing layer prior to the irradiation of the metalliferous layer with the laser. In one embodiment, the electrode and/or the conductor is fixed by a holding device, for example a gripper or a clamping device.
In one embodiment, the conductor and/or the electrode are embedded into the substrate with the help of an injection molding process.
In one embodiment, the conductor is embedded into the substrate as described above, and an electrode is subsequently formed by irradiating a metalliferous layer. In one embodiment, the conductor as well as the electrode are embedded into the substrate as described above, and the electrode is subsequently connected to the conductor by irradiating a metalliferous layer, and thus forming a coherent metal layer.
In one embodiment, the electrode and the conductor have different diameters. This refers to the smallest diameter of the electrode or of the conductor, respectively, at that location, at which a connection between the electrode and the conductor is to take place with the help of the electroconductive metal layer. This can be, for example, the diameter of a wire or the width of a conductor track. It is possible with the help of the method according to one embodiment to design the geometry of the electroconductive metal layer, which is formed by irradiation of the metalliferous layer with a laser, to be virtually arbitrary. In this way, the formation of the electroconductive metal layer can take place in such a way in one embodiment that the electroconductive metal layer forms a geometrical and mechanical gradient between the diameters of the electrode and the conductor. This means that the width and/or height of the electroconductive metal layer tapers continuously between the electrode and the conductor in order to establish an even transition between the diameters of the electrode and the conductor. A gradient at the height of the electroconductive metal layer can be attained by an increasing or decreasing layer thickness of the electroconductive metal layer. This can be attained, for example, in that the laser power and/or irradiation duration is increased accordingly by variation of the movement speed or the number of the laser pass-overs of the laser at the areas, which are to have a higher layer thickness. In the alternative or in addition, the steps of bringing the electrode and/or the conductor into contact with a metalliferous layer and the irradiation of the metalliferous layer with a laser can be repeated several times, wherein a higher number of repetitions are performed in the areas with a desired higher layer thickness.
In one embodiment, a method is therefore provided, wherein the electrode and the conductor have different diameters, and the formation of an electroconductive material layer takes place in such a way that the electroconductive metal layer forms a gradient between the diameters of the electrode and of the conductor. In one embodiment, the gradient is a geometrical and/or mechanical gradient.
In one embodiment, the method furthermore includes the removing of the metalliferous layer after the formation of the electroconductive metal layer. By the irradiation of the metalliferous layer with a laser, only a portion of the metal particles become parts of the electroconductive material layer in some cases. The remaining metal particles and optionally the carrier, which can be part of the metalliferous layer, are no longer required after the formation of the electroconductive metal layer, and can be removed. In one embodiment, the metalliferous layer is completely removed after the formation of the electroconductive metal layer. In one embodiment, the electroconductive metal layer is thereby not removed.
In one embodiment, the metalliferous layer is applied as liquid suspension, as paste, or as metal powder, as described above in more detail. The metalliferous layer can for example be applied to the substrate in such a way that it in each case partially covers the electrode and the conductor, and covers the area of the substrate located therebetween, in which the electroconductive metal layer is to form a connection between the electrode and the conductor.
In one embodiment, the electrode and/or the conductor is coated in order to improve the connection to the electroconductive metal layer. This coating can be coated, for example, with a meltable material, for example a low-melting metal. In one embodiment, the conductor is an electrically insulated wire and is coated at a non-insulated area of the wire. In one embodiment, the conductor and/or the electrode is coated with a material, which chemically reacts with the metalliferous layer. In one embodiment, the conductor and/or the electrode are coated with nanoparticles. In one embodiment, the nanoparticles are set up to chemically or physically react with the metalliferous layer, in particular with the metal or metal oxide particles contained therein. In one embodiment, the electrode and/or the conductor is coated with a material, which effects or supports the reduction of a metal oxide in the metalliferous layer.
In one embodiment, the electrode and/or the conductor is coated with a coating, which includes a polymer. In one embodiment, the polymer is a conductive polymer, for example PEDOT, or a polymer, which includes carbon particles or carbon nanotubes. In one embodiment, the coating includes a metal or an alloy. In one embodiment, the metal is platinum or gold. In one embodiment, the alloy is a nickel-titanium alloy. In one embodiment, the metal or the alloy preferably have a low melting point, for example a melting point of less than 500° C., 450° C., or 400° C. This low melting point can be attained, for example, in that the metal or the alloy are present in the form of nanoparticles. Particles with an average size diameter of less than 100 nm are referred to as nanoparticles.
In one embodiment, the electrode and/or the conductor is coated with a coating, which includes a polymer and metal nanoparticles.
In one embodiment, the electrode and/or the conductor are provided with a structure or are roughened in order to improve the connection to the electroconductive metal layer. In one embodiment, the electrode and the conductor are provided with structures, which are in each case complementary to one another. This makes it possible that the electrode and the conductor can be connected to one another in a positive manner. In one embodiment, the electrode and the conductor are connected to one another in a positive manner as well as in a non-positive manner. In one embodiment, the electrode and the conductor are connected to one another in a positive manner as well as by using a substance-to-substance bond. In one embodiment, the substance-to-substance bond of the electrode to the conductor includes the irradiation of a metalliferous layer with a laser, and thus formation of a coherent electroconductive metal layer, which connects the electrode to the conductor. In one embodiment, the substance-to-substance bond of the electrode to the conductor includes the cold welding (press fit) of the electrode to the conductor. In one embodiment, the conductor and the electrode are connected to one another by pressing.
In one embodiment, an electrically insulating layer is additionally applied to the electroconductive metal layer. In one embodiment, the electroconductive metal layer is covered completely by the electrically insulating layer. In one embodiment, the electrically insulating layer includes a polymer. In one embodiment, the polymer is selected from the group consisting of silicon, polyethylene, polyurethane, polyimide, polyamide, PEEK, fluorinated plastics. Fluorinated plastics are, for example, ETFE, PTFE, PFA, PVDF, or FEP.
A further aspect of one embodiment relates to an electrode-conductor composite, which is produced or can be produced according to any one of the above-described methods. An electrode-conductor composite includes an electrode, which is connected to a conductor in an electroconductive manner. In one embodiment, the electrode-conductor composite is electrical medical device or a part of a device of this type. The electrical medical device can be, e.g., a lead, pulse generator, pacemaker, cardiac resynchronization device, catheter, sensor, or stimulator. Leads are electrical lines, which can be used, for example, in medical applications, such as neuromodulation, cardiac stimulation, deep brain stimulation, spinal cord stimulation, peripheral nerve stimulation, or gastric stimulation. Examples for catheters according to one embodiment are those, which are set up for the electrophysiological mapping or the ablation of tissue. In one embodiment, the lead is set up and/or intended to be connected to a generator of an active implantable device. A lead of one embodiment can also be used in a medical device in order to receive an electrical signal. A stimulator is a medical device, which can have a physiological effect by outputting an electrical signal to the body of a living being. For example, a neurostimulator can effect an electrical signal in the nerve cell (e.g. an action potential) by outputting an electrical signal to a nerve cell. A further embodiment relates to a microelectrode or a microelectrode array, which includes an electrode-conductor composite described herein.
A further aspect relates to the use of laser irradiation of a metalliferous layer, and thus forming an electrical connection for producing an electrode-conductor composite. This use can be, for example, for one of the methods described herein.
Embodiments will be described in more detail below on the basis of the figures in several examples. These examples serve to further illustrate the embodiment. It is not intended that these examples are to limit the scope of protection of this patent application.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments illustrated and described without departing from the scope of the present embodiments. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that these embodiments be limited only by the claims and the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019006709.6 | Sep 2019 | DE | national |
