METHOD AND DEVICE FOR PRODUCING AN ELECTRICAL CONNECTION CONTACT ON A COATED SHEET

Description

Technical area

[0001] The invention relates to a device and a method for producing an electrical connection contact on a coated sheet metal, the coating of which has at least one electrical conductor track covered by an electrical insulation layer, in which method a recess is created through the electrical insulation layer at least up to the electrical conductor track and in this recess an electrically conductive contact element is provided, which electrically connects to the conductor track at one end and forms the electrical connection contact at the other end. State of the art

[0002] In order to electrically connect a conductor embedded in a coating on a metal sheet, it is known from the prior art (EP1517597A2) to push a contact pin through the electrical insulation of the coating to the electrical conductor. This electrically connects the contact pin to the conductor at one end, while its other end forms an electrical connection. Disadvantages of pushing in a contact pin in this way can be comparatively difficult or imprecisely reproducible – and impact-induced deformations of the contact pin can also make targeted contacting difficult. Prior art methods are therefore comparatively error-prone.

[0003] Further relevant prior art is disclosed in document US 5 844 753 A.

[0004] A cannula for forming a through-hole or recess and for filling it with conductive adhesive is known from DE10206440A1. Description of the invention

[0005] It is therefore an object of the invention to simplify or improve a method for producing an electrical connection contact on a coated sheet of the type described above - and thus to increase the reproducibility of the method.

[0006] The invention solves the stated problem by a method according to claim 1. The recess is formed with the aid of a hollow needle which is advanced in the direction of the conductor track and which, when withdrawn from the recess, introduces an electrically conductive, viscous mass into this recess in order to produce the contact element.

[0007] If the recess is formed using a hollow needle pushed forward in the direction of the conductor track, a precisely positioned and comparatively exact recess can be created in the coating, regardless of the mechanical strength of a contact element, which opens the coating up to the conductor track. Among other things, this also prevents short circuits, for example with other conductor tracks. If the contact element is then provided in such a recess by introducing an electrically conductive, viscous mass into the recess as the hollow needle is withdrawn from the recess in order to create the contact element, the precise recess can be used to precisely shape the contact element - and thus also provide a reproducible electrical connection between the outer connection contact and the electrical conductor track with the same electrical properties. In addition, this pushing forward orRetraction of a hollow needle is comparatively easy to handle, which can further increase the reproducibility of the procedure.

[0008] The reproducibility of the process can be further increased if a paste or ink is introduced as a viscous mass.

[0009] In general, it is mentioned that an electrically conductive polymer, for example polyaniline, polypyrrole, or polythiophene, can be used as the electrically conductive paste / ink for forming the contact element. Such a paste / ink can also have a metallic base, such as silver, copper, or gold, an organic base, such as PEDOT (poly-3,4-ethylenedioxythiophene), or a graphene base. Carbon or graphite are also conceivable. Metallic-based inks / pastes can be characterized by particularly favorable conductivity, whereas organic-based inks and / or pastes can usually offer increased corrosion resistance. A paste generally has a higher viscosity, for example > 50 mPa s, preferably > 1 Pa s, than an ink. For example, PEDOT:PSS can be produced as an ink or as a paste.This can be adjusted, for example, by the amount of solvent, such as water or isopropanol.

[0010] The contacting of the conductor track can be further improved if at least one parameter, which depends on the distance between the hollow needle and the conductor track, is measured as the hollow needle advances. This limits the depth of the hollow needle toward the sheet. This allows the depth of the recess to be determined and adjusted with particular precision, even with varying coating thicknesses—which in turn can increase the reproducibility of the process.

[0011] The feed depth can, for example, be set reproducibly if this parameter, which depends on one of the dielectric constants between the hollow needle and the conductor track, is measured.

[0012] Alternatively, it is conceivable that the feed depth is adjusted by measuring a parameter dependent on the eddy current principle.

[0013] The feed depth can also be adjusted precisely by measuring a variable that depends on the inductive measuring principle.

[0014] If the hollow needle pierces the electrical insulation layer, the displacement of the coating can ensure that the contact element remains precisely fixed in its position, even if the contact element shrinks due to hardening or drying of the viscous mass.

[0015] Low-resistance contacting of the conductor track can be achieved by advancing the hollow needle to the side of the electrical conductor facing the sheet metal. This can further increase the reproducibility of the process.

[0016] A stable electrical connection contact can be created if the viscous mass is dried and / or cured to create a solid contact element.

[0017] The curing and / or drying of the compound can occur actively or passively directly after application. With passive curing, such as with a silver paste, the compound is cured and / or dried in air without actively accelerating the process. This type of process step is comparatively simple to handle, which can increase the reproducibility of the process. Passive curing and / or drying is preferably performed with pasty, viscous compounds, namely pastes, as these are more resistant to undesirable deformation of the recess, for example, due to springback and / or reflow of the electrical insulation layer.

[0018] Active curing and / or drying can be achieved by UV irradiation or heating of the applied conductive paste. Active curing is particularly advantageous for low-viscosity inks. For example, the viscous mass can be exposed to UV rays directly after insertion and / or during retraction of the hollow needle. This type of active curing and / or drying is particularly suitable for low-viscosity masses, such as inks, as these are particularly susceptible to undesirable deformation at the recess.

[0019] Alternatively, a thermal treatment with, for example, an infrared lamp field at 40°C to 150°C, preferably 60°C to 100°C for in particular 0.5 to 100 seconds, preferably 5 to 60 seconds, can be provided in order to accelerate the curing.

[0020] Pre-drying and / or pre-curing the viscous mass in the hollow needle before inserting it can help ensure the dimensional accuracy of the contact element. Such "in-situ" curing can be achieved electrochemically, for example. It is conceivable to transfer electrical energy to the hollow needle via a contact point on the conductor track, thereby stimulating the viscous mass to harden, for example, in the chemical reaction. It is also conceivable for this electrical excitation to occur in the hollow needle itself. Advantageously, the speed of the curing reaction can be controlled directly and relatively easily by regulating the current.

[0021] The dimensional accuracy of the contact element can be further improved if the viscous mass is pre-dried and / or pre-cured in such a way that this viscous mass exhibits increasing hardness from the inside to the outside. Furthermore, this curing, which occurs more frequently at the interface, can make the process efficient and reproducible and also further increase the dimensional stability of the applied paste. In addition, such pre-drying and / or pre-curing can create a clearance between the recess and the contact element, into which cavity electronic / electrical components / parts or other materials can be provided.

[0022] If the opening at the head of the hollow needle is closed when forming the recess by advancing it toward the conductor track, this prevents any penetrating the hollow channel. This allows a reproducible high-quality contact element to be created in which the opening at the head remains open when the hollow needle is withdrawn from the recess, allowing the electrically conductive, viscous compound to be introduced into the recess through this opening.

[0023] The invention also has the object of creating a device with which an electrical connection contact can be made on a coated sheet in a stable manner.

[0024] The invention solves the stated problem by a device according to claim 12 with at least one hollow needle which receives a viscous mass and has at least one sensor for detecting at least one measured variable which is dependent on the distance to the hollow needle.

[0025] If the hollow needle accommodates a viscous mass and has at least one sensor for detecting at least one measured variable that is dependent on the distance to the hollow needle, a relatively simple means of reliably establishing an electrical connection can be provided. This measured variable, which is dependent on the distance to the hollow needle, can depend, for example, on the distance between the hollow needle and the conductor track, the distance between the hollow needle and the sheet metal, etc.

[0026] A device which is fast in the production of an electrical connection contact on a coated sheet can be created if the device has several hollow needles guided in parallel for the joint production of several electrical connection contacts.

[0027] If the hollow needle has a shut-off nozzle at the opening in its head, complete displacement of the material, for example from the insulation layer, in front of the hollow needle can be ensured when the hollow needle is advanced to form the recess. For example, this can also prevent material from penetrating the hollow needle channel of the hollow needle and avoid impairing the electrically conductive, viscous mass. This can enable a more stable production of an electrical connection. If, in addition, a valve element of the shut-off nozzle is movably arranged in the hollow needle channel for opening or closing the opening on the head, the hollow needle can have slim dimensions despite having a shut-off nozzle on the head, thus making it easier to advance the hollow needle. Short description of the drawings

[0028] The figures show, for example, process steps of the method according to the invention. Fig. 1 a sectional view of a coated sheet with a hollow needle penetrating into its coating according to a first embodiment, Fig. 2 a sectional view of the Fig. 1 shown sheet with retracted hollow needle, Fig. 3 a sectional view of the Fig. 1 shown sheet with a connection contact, Fig. 4 a torn and enlarged sectional view of the hollow needle according to Fig. 1 and Fig. 5a, 5b shows a hollow needle according to a second embodiment. Ways to implement the invention

[0029] After the Figures 1, 2 and 3A sheet 1, preferably thin sheet, in particular made of a steel material, is shown, which sheet 1 is provided with a coating 2. This coating 2 consists of a primer 3 applied to the sheet 1, for example a primer, an electrical conductor 4 provided on the primer, and an electrical insulation layer 5, for example a topcoat, which covers the conductor 4 to the outside.

[0030] In addition, Fig. 3an electrical connection contact 6, via which the conductor track 4 can be electrically connected. The electrical connection contact 6 is formed by an electrically conductive contact element 7. For this purpose, the contact element 7 protrudes through a recess 8 in the electrical insulation layer 5 to the electrical conductor track 4 and thus contacts the conductor track 4. As a result, the contact element 7 is electrically connected to the conductor track 4 at a first end 7.1, with the contact element 7 forming the electrical connection contact 6 at the other, second end 7.2.

[0031] According to the invention, the recess 8 is produced in a special way, namely, with the aid of a hollow needle 10 advanced in the direction 9 of the conductor track 4 - as shown in the Figures 1 and 2 can be seen according to a first embodiment.

[0032] Instead of the hollow needle 10 in the Figures 2 to 4 can also be one according to the Figures 5a, 5bshown hollow needle 110 may be used, which is generally mentioned.

[0033] Accordingly Fig. 1 the hollow needle 10 has penetrated into the coating 2 - after Fig. 2 this hollow needle 10 is shown already advanced to the conductor track 4.

[0034] This introduction of the hollow needle 10 results in a particularly precisely running recess 8 in the coating 2 or in the electrical insulation layer 5.

[0035] When the hollow needle 10 is withdrawn from the recess 8, the hollow needle 10 introduces an electrically conductive viscous mass 11, namely a paste, into this recess 8, which creates the fixed contact element 7 in the recess 8, for example by hardening and / or drying, etc. of the mass 11. The withdrawn position of the hollow needle 10 comes into Fig. 3 to expression.

[0036] Since the hollow needle 10 is comparatively easy to handle and the precisely extending recess 8 also allows a precisely positioned contact element 7 for an electrical connection contact 6 to be produced on the coated sheet 1, the invention is distinguished from the prior art by its high reproducibility.

[0037] In addition, the process of creating the recess 8 by the hollow needle 10 and introducing the conductive viscous mass 11 into this recess 8 upon retraction of the hollow needle 10 can be carried out continuously, which speeds it up and also makes it more efficient.

[0038] The penetration depth of the hollow needle 10 into the coating 2 is adjusted by a controller 12, which regulates / controls the feed rate 9 of the hollow needle 10. For this purpose, a measuring device 13 is assigned to the controller 12, which transmits to the controller 12 a measured variable 14 dependent on one of the dielectric constants between the hollow needle 10 and the sheet 1. This measurement, which can be, for example, a capacitance measurement using the electrically conductive casing 10.1 of the hollow needle 10 as a sensor 19.1, can be used to determine the distance of the hollow needle tip from the sheet 1 - whereby the feed rate of the hollow needle 10 in the direction of the sheet 1 can be limited or precisely adjusted.

[0039] Alternatively or in addition to this capacitively acting first sensor 19.1 of the hollow needle 10 according to Fig. 4 Inductive and / or eddy current sensors 19.2, 19.3 associated with the hollow needle 10 are also conceivable, as shown in Fig. 4indicated can be recognized in order to be able to measure the distance reliably.

[0040] For this purpose, the hollow needle points Fig. 4 a first electrical coil 20 as the second sensor 19.2, which first coil 20 is attached to the outside of the casing 10.1 of the hollow needle 10. With the help of this first coil 20, eddy currents are induced in the conductor track and / or sheet metal. Based on the change in the impedance of the first coil 20, the electromagnetic shielding of the sheet metal 1 by the overlying conductor track 4 can be detected, and the distance between the hollow needle 10 and the conductor track 4 can be determined.

[0041] Alternatively or additionally, the hollow needle 10 can have a second electrical coil 21 provided on the outside of the casing 10.1 as a third sensor 19.3. In this measuring method, the first coil 20 serves to generate a magnetic field. The second coil 21 measures a voltage proportional to the magnetic flux generated by the first coil 20. Since the conductor track 4 embedded in the coating 2 causes a change in the magnetic flux, the voltage at the second coil 21 can be used to locate the hidden conductor track, and the distance between the hollow needle 10 and the conductor track 4 can be calculated.

[0042] As in the Figures 1 and 2As can be seen, the hollow needle 10 pierces the electrical insulation layer 5 to form the recess 8. However, it is also conceivable that the hollow needle 10 uses a machining process to form the recess 8. For this purpose, the hollow needle 10 can have at least one cutting edge (not shown in detail), for example, from an indexable insert. The cutting edge (not shown in detail) can be Fig. 4 or Fig. 5a on the casing 10.1 and / or on the head 10.2 of the hollow needle 10 in order to machine the electrical insulation layer 5.

[0043] A secure electrical contact with low resistance is created by advancing the hollow needle 10 to the conductor side 4.1 of the electrical conductor track 4 facing the sheet 1.

[0044] The viscous mass 11 is cured with a radiation source 15, namely a UV lamp, thereby creating a solid and thus dimensionally stable contact element 7. Alternatively or additionally to the UV lamp, a thermal heat source such as an IR lamp array can be provided. The solidification (e.g., drying, curing, chemical crosslinking, etc.) of the viscous mass 11 can be performed during and / or after the introduction of the viscous mass 11 into the recess 8. It is also conceivable for the solidification of the viscous mass 11 to occur in a process step following the production of an electrical connection contact 6.

[0045] In addition, as in Fig. 4As can be seen in detail, before the viscous mass 11 is introduced, it is pre-solidified in the hollow needle 10, namely pre-cured by cross-linking. For this purpose, the hollow needle has an electrically insulating coating 17 on the inside of the casing 10.1. An electrode 18, e.g., a Pt wire, is also provided centrally in the hollow needle 10. This electrode 18, e.g., a Pt wire, interacts with the electrically conductive casing 10.1 as a counter electrode to stimulate a chemical hardening reaction (e.g., polymerization) in the viscous mass 11 when electrical energy is applied between the two electrodes. This allows in-situ hardening of the viscous mass 11 to take place before it is introduced into the recess 8. In particular, the viscous mass 11 can be pre-dried and / or pre-cured in such a way that this mass 11 has a hardness that increases from the inside to the outside.

[0046] A device 22 for the parallel production of several electrical connection contacts 6 is also provided in Fig. 1 Here, several hollow needles 10 are guided in parallel by the device 22, specifically with the same feed rate 9. The hollow needles 10 are positioned at a distance from one another on the sheet 1, for example, one after the other and next to one another, and can thus, for example, create the connecting contacts 6 of an electrical interface (not shown in detail). This can create an interface quickly in a simple and efficient manner.

[0047] It is also generally mentioned that the hollow needle can be blunt or tapered. Blunt penetration exposes the electrical insulation layer to as little stress as possible, whereas a tapered shape can reduce the penetration force. Furthermore, a blunt shape can facilitate the acquisition of measurement data and thus make the procedure more precise.

[0048] As in the Figures 5a and 5bAs can be seen, according to a second embodiment, the hollow needle 110 has a shut-off nozzle 16 on the head 10.2. This shut-off nozzle 16 serves to open and close the opening 10.3 on the head 10.2 of the hollow needle 110. This is made possible by a tappet-shaped valve element 16.1 of the shut-off nozzle 16, which valve element 16.1 is arranged to be linearly movable in the hollow needle channel 10.4. When the shut-off nozzle 16 is closed, the valve element 16.1 closes the opening 10.3 on the head 10.2, and when the shut-off nozzle 16 is open, the valve element 16.1 is displaced back relative to the opening 10.3, thus allowing the electrically conductive, viscous mass 11 to flow. This prevents internal contamination of the hollow needle 110 or its electrically conductive, viscous mass 11. This occurs, for example, when the hollow needle 110 is pushed through a material to form the recess 8.The hollow needle 110 according to the invention thus always ensures a high-quality electrical connection contact 6, which particularly increases the stability of the method.

Claims

1. A method for producing an electric terminal contact (6) on a coated sheet (1), whose coating (2) has at least one electric conductor path (4) covered by an electrical insulation layer (5), in which method a recess (8) is produced extending through the insulation layer (5) at least to the electrical conductor path (4) and in this recess (8), an electrically conductive contact element (7) is provided, one end (7.2) of which is electrically connected to the conductor path (4) and at the other end (7.1) of which forms the electrical terminal contact (6), characterized in that the recess (8) is produced with the aid of a hollow needle (10), which is advanced in the direction toward the conductor path (4) and which, as it is withdrawn from the recess (8), introduces an electrically conductive, viscous compound (11) into this recess (8) in order to produce the contact element (7), wherein when the hollow needle (10) is advanced, at least one measurement variable (14), which depends on the distance between the hollow needle (10) and the conductor path (4), is measured in order to limit the advancing depth of the hollow needle (10) in the direction toward the sheet (1).

2. The method according to claim 1, characterized in that a paste or an ink is introduced as the viscous compound (11).

3. The method according to claim 1, characterized in that a measurement variable (14) is measured, which depends on one of the permittivities between the hollow needle (10) and the conductor path (4).

4. The method according to claim 1, characterized in that a measurement variable (14) is measured, which depends on the eddy current principle.

5. The method according to claim 1, characterized in that a measurement variable (14) is measured, which depends on the inductive measurement principle.

6. The method according to one of claims 1 to 5, characterized in that the hollow needle (10) pierces the electrical insulation layer (5).

7. The method according to one of claims 1 to 6, characterized in that the hollow needle (10) is advanced until it reaches the conductor side (4.1) of the electrical conductor path (4) that faces the sheet (1).

8. The method according to one of claims 1 to 7, characterized in that the viscous compound (11) is dried and / or cured in order to produce a solid contact element (7).

9. The method according to claim 8, characterized in that the viscous compound (11) is pre-dried and / or pre-cured in the hollow needle (10) before being introduced.

10. The method according to claim 9, characterized in that viscous compound (11) is pre-dried and / or pre-cured in such a way that this viscous compound (11) has a hardness that increases from the inside to the outside.

11. The method according to one of claims 1 to 10, characterized in that when the recess (8) is produced with the aid of a hollow needle (10) that is advanced in the direction toward the conductor path (4), its opening (10.3) is closed at the top (10.2) and when the hollow needle (10) is withdrawn from the recess (8), its opening (10.3) at the top (10.2) is open to introduce the electrically conductive viscous compound (11) into this recess so as to produce the contact element (7).

12. An apparatus designed for carrying out the method according to one of claims 1 to 11 with at least one hollow needle (10), which accommodates a viscous compound (11) and has at least one sensor (19.1, 19.2, 19.3) for detecting at least one measurement variable (14), which measurement variable (14) depends on the distance from the hollow needle (10) and the conductor path (4) of the sheet (1).

13. The apparatus according to claim 12, characterized in that the apparatus (22) has a plurality of parallel-guided hollow needles (10) for jointly producing a plurality of electrical terminal contacts (6).

14. The apparatus according to claim 12 or 13, characterized in that at the opening (10.3) of its head (10.2), the hollow needle (10) has a shut-off nozzle (16); a valve element (16.1) of the shut-off nozzle (16) is supported so that it is able to move in the hollow needle duct (10.4) in order to open or close the opening (10.3) in the head (10.2).