EP4154689A2

EP4154689A2 - Process for manufacturing a component, assembly, and method for electrically contacting the printed circuit board of the component or of the assembly

Info

Publication number: EP4154689A2
Application number: EP21728053.6A
Authority: EP
Inventors: Franz Padinger; Jürgen Goldmann; Marius SILLAMNN
Original assignee: Scio Holding GmbH
Current assignee: Scio Holding GmbH
Priority date: 2020-05-22
Filing date: 2021-05-21
Publication date: 2023-03-29
Also published as: WO2021234146A3; WO2021234146A2; US20230209703A1; CN115720728A

Abstract

The invention relates to a method for producing a component (1) which comprises a printed circuit board (2) and a plurality of electrical components (3) arranged thereon. According to the invention, the electrical components (3) are pre-fixed on the printed circuit board made of plastic by means of a fixing adhesive (9) and are subsequently fully cast with a UV adhesive (8).

Description

Process for manufacturing a component

The invention relates to a method for producing a component according to the features of the preamble of claim 1.

From the prior art, as described in DE 102014008262 A1, a backlit car emblem, in which only the car trademark is illuminated, is known. The LED-backlit car brand emblem in the rear area of a motor vehicle is coupled with the parking lights and the low beam as well as directly with the license plate light in the rear area and is also switched on and off with this.

The invention is based on the object of specifying a method for producing a component which is improved over the prior art.

The object is achieved according to the invention by a method for producing a component having the features of claim 1.

Advantageous refinements of the invention are the subject matter of the subclaims.

According to a first aspect, a method for producing a component is provided which comprises a printed circuit board and a plurality of electrical components arranged thereon. H. completely encapsulated with an adhesive that can be hardened by means of ultraviolet radiation.

The electrical components are therefore bonded in two stages. When the adhesive hardens or polymerizes, water can in principle be split off. This allows conductor tracks and contacts from electrical implementation to be damaged. The two-stage bonding has the advantage that a thin layer of fixing adhesive is applied first, which hardens, with the resulting water escaping. When the adhesive is completely potted, water is again produced as the adhesive hardens and polymerizes. Since the corrosion-sensitive parts, such as conductor tracks and contacts of the electrical components, are already covered by the first, essentially hardened adhesive layer, they are protected from the moisture that occurs when the second adhesive layer hardens. This is particularly advantageous if the component to be produced in this way has a cavity to be poured, which is almost completely closed after the pouring, so that the moisture that occurs during polymerisation can only escape slowly. In the case of a component that consists of two or more parts to be glued together, the fixing adhesive is initially exposed after the first gluing step, so that it can dry quickly and easily.

In particular, an emblem is formed as a component, in particular an illuminated emblem, in particular a brand emblem of a vehicle manufacturer, which can be attached to a vehicle. The electrical components, which are pre-fixed by means of the fixing adhesive, include, in particular, LEDs (light-emitting diodes) for illuminating the emblem. The method according to the invention ensures environmentally stable and light-optimized bonding of the electrical components to the plastic printed circuit board.

In particular to form the emblem, the printed circuit board, in particular made of polymethyl methacrylate (PMMA), with the electrical components pre-fixed thereon, is advantageously connected to a cover, in particular glued, after the fixing adhesive used for pre-fixing has hardened. The cover is formed, for example, from polycarbonate (PC) and / or acrylonitrile-butadiene-styrene (ABS) and / or from one or more other materials. For example, the cover is chrome-plated, in which case it is formed, for example, from polycarbonate and acrylonitrile-butadiene-styrene (PC / ABS) or from acrylonitrile-butadiene-styrene (ABS) or from one or more other materials. Gluing takes place in particular by completely filling an adhesive channel between the circuit board and the cover, also known as the chrome cover, if it is chrome-plated, and then irradiating the UV adhesive through the translucent circuit board using a UV lamp thereby hardening. This form of bonding means that shear forces no longer act directly on the individual electrical components, but on the entire pre-fixing of all components of the component. As a result, the electrical components stick to the conductor tracks of the circuit board and the component meets the framework conditions for environmental influences required by the method described.

The method described here is used to manufacture the component, in particular the illuminated emblem, in such a way that the electrical components are protected from environmental influences, which in particular lead to the entry of moisture and thus to corrosion of the conductor tracks of the circuit board, in particular also at temperatures between - 30 ° C and 80 ° C and also with different operating states of the component. The method also ensures that the LEDs produce a homogeneous light image on the emblem.

Without the inventive pre-fixing of the electrical components on the circuit board, d. H. If the electrical components were only fully encapsulated on the circuit board, the electrical components would also be protected, for example at least at room temperature, but the coefficients of thermal expansion of all components of the component differ so greatly in the case of large temperature differences that the shear forces exerted by the UV adhesive on the electrical Components would be transferred so large that the electrical components would be torn from the conductor tracks. Furthermore, with this exclusive full encapsulation, no homogeneous light image can be created without prior pre-fixing.

These disadvantages are thus avoided by the method described here. The pre-fixing of the electrical components on the circuit board prevents the shear forces between the UV adhesive and the electrical components from becoming too high. In addition, this protects the conductor tracks, which are in particular made of silver, from a chemical reaction with the UV adhesive.

The electrical components are pre-fixed on the printed circuit board, for example, by applying the fixing adhesive for pre-fixing the electrical components by means of a valve, in particular by means of a jet valve, to a mounting device designed in particular as an SMD mounter, by means of which the electrical components are mounted the circuit board is applied, is applied at least in sections to the circuit board and the electrical components, in particular in such a way that it wets the conductor tracks and encloses the electrical components and is attached to the circuit board. In the case of LEDs, the fixing adhesive is advantageously applied in such a way that the LEDs are left exposed in the main emission direction, i.e. not covered with the fixing adhesive, in order to avoid undesirable color effects of a light emitted by the LEDs, which would result from a change of media, i.e. an undesired change of the medium through which the light shines. As an alternative to applying the fixing adhesive by means of the assembly device, the fixing adhesive can also be applied at a different location and / or with a different device.

According to a second aspect of the invention, an electrical assembly is provided, comprising a printed circuit board and a plurality of LEDs arranged thereon, wherein

- the circuit board is made of plastic,

The LEDs are divided into several component groups, the LEDs of each component group being connected electrically in series and the component groups being connected electrically in parallel to one another, each component group comprising a plurality of electrical series resistors which are electrically connected in series with the LEDs of the respective component group , an electrical series resistor and at least one LED being arranged alternately one after the other.

An electrical assembly comprises a printed circuit board and a plurality of LEDs (light-emitting diodes) arranged thereon.

In particular, an electrical series resistor and an LED are arranged alternately.

In addition, a resistance value of the electrical series resistors of the respective component group is advantageously higher than is necessary for a permissible current flow through the LEDs of the respective component group. The permissible current flow is specified by the manufacturers of the LEDs. As a result, the light-emitting diodes are operated in normal operation with a current flow well below the maximum permissible current flow.

Furthermore, conductor tracks on the circuit board, which are designed in particular as silver conductor tracks by means of screen printing, are at different positions PCB a different thickness. Different thicknesses mean conductor tracks of different widths in the top view, since the layer thickness as such cannot be changed in screen printing.

The electrical assembly according to the invention can be used, for example, to form an illuminated emblem, in particular to form an illuminated brand emblem of a vehicle manufacturer that can be attached to a vehicle. In particular, when the electrical assembly is used in this way, it is not possible to cool the electrical assembly in a conventional manner. With the solution according to the invention, such cooling is not necessary, since this solution according to the invention achieves thermal optimization and thus functioning thermal management of the electrical assembly.

Without the solution according to the invention, for example dividing the LEDs into groups of two and three, each with a single series resistor designed for an effective voltage of 10 V, for example, individual failures would occur in prescribed electrical load tests, for example with a transient overvoltage of 17 V for 60 minutes LED groups come from massive heat development from individual electrical series resistors, which melt into the printed circuit board, which is made in particular of a thermoplastic, and cut through the printed silver conductor tracks. The heat development also takes place asymmetrically on the circuit board and especially in the area of a voltage feed.

This is prevented by the solution according to the invention, because in the solution according to the invention, as described above, a variable thickness of the screen-printed conductor tracks is used in order to thereby achieve a resistance control of the conductor tracks.

Furthermore, the optimization according to the invention is carried out for the thermal management by means of the electrical series resistors, which are oversized in the solution according to the invention and are delocalized on the circuit board, ie not one electrical series resistor per component group, but the resistance value, which is also greater than required divided into several series resistors per component group and these are arranged distributed on the circuit board, in particular alternately one electrical each Series resistor and an LED. As a result, a thermally stable electrical circuit is achieved on the plastic printed circuit board by means of the solution according to the invention.

Without the solution according to the invention, the electrical assembly and thus the component, in particular designed as an emblem, would not be able to meet the electronic requirements. For example, an expensive series circuit board would then also be required to reduce the voltage, which is avoided by the solution according to the invention.

According to a further aspect of the present invention, a method for electrically conductive contacting of a circuit board is provided. The circuit board is made in particular from plastic. In the method, a contact pin, in particular made of brass, penetrates the printed circuit board, i. E. H. from one flat side in the direction of an opposite flat side of the circuit board, pressed into the circuit board, in particular in a form-fitting manner, until a collar formation at a front end of the contact pin rests on a bottom of a groove-like recess in the circuit board. This end is covered with a printed conductor, in particular made of silver, in the groove-like depression. The contact pin is crimped with a crimp barrel. An electrical cable, in particular with a cable end sleeve, is inserted into the crimp sleeve, electrically conductively contacted with the contact pin and crimped with the crimp sleeve. A shrink tube is sealingly arranged over the contact pin, the crimp sleeve and at least in sections over the electrical cable, in particular over the cable end sleeve, ie. H. shrunk. The circuit board is advantageously equipped and / or glued to at least one other component before the contact pin is crimped with the crimp sleeve.

The crimp barrel is crimped with the contact pin in particular such that the contact pin is locked in its position in the circuit board by the crimp barrel, with the crimp barrel preventing or at least restricting movement of the contact pin in the longitudinal direction of the contact pin. The crimp sleeve in particular prevents the contact pin from being pushed back against the press-in direction, which in particular keeps contacting of the contact pin to conductive pastes and / or to the conductor track at the end of the contact pin in function. By means of the solution according to the invention, in industrially manufactured circuit boards, in particular made of plastic, with in particular screen-printed conductor tracks, a sensible and environmentally stable electrically conductive contact for cables can be produced. In particular, this solution according to the invention prevents the electrically conductive connection of the cable from loosening caused by temperature interactions and environmental influences.

In the case of direct electrically conductive contact between the conductor tracks and the cable or other connecting elements, due to the different coefficients of thermal expansion of the materials involved and a low connection force to the conductor tracks, a thermally induced movement would be sufficient to separate the connection and thus to errors in the electrical contact respectively. This is avoided by the solution according to the invention.

The solution according to the invention is used, for example, for electrically conductive contacting of a printed circuit board of an emblem, in particular an illuminated emblem, in particular a brand emblem of a vehicle manufacturer, which can be attached to a vehicle.

The different aspects of the invention explained above can be used independently of one another or in any combination.

Embodiments of the invention are explained in more detail below with reference to drawings.

Show:

1 schematically shows a sectional illustration of an embodiment of a component without gluing its components, 2 schematically shows a plan view of a printed circuit board of the component with electrical components pre-fixed at certain points,

3 schematically shows a plan view of a printed circuit board of the component with electrical components that are pre-fixed over a large area,

4 schematically shows a sectional illustration of a further embodiment of the component with bonded components,

5 schematically shows a partial sectional illustration of a portion of the component, and

6 shows a schematic plan view of a detail of an electrical assembly.

Corresponding parts are provided with the same reference symbols in all figures.

A method for producing a component 1 is described below with reference to FIGS. 1 to 4. The component 1 comprises a printed circuit board 2 and a plurality of electrical components 3 arranged thereon.

In the example shown, the component 1 is an illuminated emblem, in particular a brand emblem of a vehicle manufacturer, which can be attached to a vehicle. The electrical components 3 include, in particular, LEDs for illuminating the emblem and, in the example shown, additional electrical resistors. They can also include other electrical components.

As already mentioned, the component 1 comprises an assembly 17 with the printed circuit board 2, which is formed here from an in particular thermoplastic material, in the example shown from polymethyl methacrylate (PMMA). Conductor tracks 4, in particular made of silver, are arranged on the circuit board 2. The conductor tracks 4 are printed on the circuit board 2, in particular screen-printed. The electrical components 3 are arranged on the conductor tracks 4. The circuit board 2 is advantageously embodied as opaque and translucent, so that light emitted by the LEDs can radiate through it in a diffusely scattering manner. The circuit board 2 thus also forms a diffuser.

A cover 5 is provided to protect the electrical components 3, in particular the LEDs, and to form the emblem. This cover 5 is formed, for example, from polycarbonate (PC) and / or acrylonitrile-butadiene-styrene (ABS) and / or from one or more other materials. For example, this cover 5 is chrome-plated. It is then also known as a chrome cover, for example. If the cover 5 is chrome-plated, the cover 5 is made, for example, of polycarbonate and acrylonitrile-butadiene-styrene (PC / ABS) or of acrylonitrile-butadiene-styrene (ABS) or of one or more other materials. The cover 5 forms, for example, a decorative part of the component 1. On an inside of the cover 5 facing the LEDs, a reflector film 6, for example white, is arranged. By means of this design of the component 1, the emission of the light from the LEDs shown by means of light rays S is achieved.

In order to be able to fasten the component 1 designed as an emblem to the vehicle, an adhesive tape 7 is also provided in the example shown, which is arranged on an underside of the circuit board 2 facing away from the LEDs.

In particular for the component 1 designed as an emblem that can be attached to the vehicle, it is necessary to connect the circuit board 2 to the cover 5 in such a way that the electrical components 3 on the circuit board 2 are protected from environmental influences, which in particular lead to moisture ingress and thus to corrosion of the conductor tracks 4 lead, are protected. This protection must also be ensured at temperatures between -30 ° C and 80 ° C and also in different operating states of the component 1. Furthermore, a homogeneous light image for illuminating the component 1 embodied as an emblem is to be generated by means of the LEDs.

To achieve this, complete encapsulation of the electrical components 3, for example by means of a UV adhesive 8, is conceivable. With such an exclusive full encapsulation, the electrical components 3 would indeed be protected against environmental influences at room temperature, but if there are large temperature differences, the thermal expansion coefficients of all components of the would differ The component 1 is so strong that the shear forces that are transferred from the UV adhesive 8 to the electrical components 3 are so great that the electrical components 3 are torn from the conductor tracks 4. Furthermore, a homogeneous light image cannot be generated in this way.

Therefore, in the method described here, provision is made for the electrical components 3 to be first pre-fixed on the printed circuit board 2 made of plastic, in particular by means of a fixing adhesive 9, and only then to be fully encapsulated. I. E. which the electrical components 3, after they have been pre-fixed on the circuit board 2, are completely encapsulated with the UV adhesive 8, whereby the cover 5 is advantageously also connected to the circuit board 2.

This pre-fixing of the electrical components 3 on the plastic circuit board 2 prevents the shear forces between the UV adhesive 8 and the electrical components 3 from becoming too high, and in addition, the conductor tracks 4 made of silver are protected from a chemical reaction with the UV -Adhesive 8 protected.

The fixing adhesive 9 is, for example, an acrylic-based adhesive that cures with UV light. The UV adhesive 8 can be an adhesive with two curing mechanisms, in particular an adhesive that cures with UV light and with moisture. The UV adhesive 8 can also be formed on an acrylate basis. Such adhesives with two curing mechanisms are sold, for example, by the company Delo (www.delo.de) under the brand name DUALBOND ^® .

When curing with UV light, moisture can be released. The second hardening mechanism absorbs the moisture again and converts it into the polymer. This means that no residual moisture remains in the finally cured component. The conductor tracks, especially if they are made of silver, are sensitive to corrosion. Conductor tracks made of copper form a patina under the influence of moisture, which can change the electrical resistance. The layer of fixing adhesive 9 covers the conductor tracks during the second gluing step and protects them from the temporary moisture. Since the printed circuit board 2 is exposed when the fixing adhesive 9 is applied, the can during the hardening of the fixing adhesive 9 Any moisture that arises can escape quickly and completely without damaging the conductor tracks 4.

For pre-fixing, the fixing adhesive 9 is applied, for example, by means of a valve, in particular by means of a jet valve, in a mounting device designed in particular as an SMD assembler, by means of which the electrical components 3 are also applied to the circuit board 2, in particular in such a way that the fixing adhesive 9 wets the conductor tracks 4 and encloses the electrical components 3 and fastened them to the circuit board 2. In the case of the LEDs, the fixing adhesive 9 is advantageously applied in such a way that the LEDs are left free in the main emission direction in order to avoid undesired color influences due to media changes. As an alternative to applying the fixing adhesive 9 by means of the assembly device, the fixing adhesive 9 can also be at a different location, i. H. not necessarily at the location at which the circuit board 2 is fitted and / or applied with another device. The application of the fixing adhesive 9 then also takes place in particular such that the fixing adhesive 9 wets the conductor tracks 4 and encloses the electrical components 3 and is attached to the circuit board 2. In the case of the LEDs, the fixing adhesive 9 is advantageously also applied in such a way that the LEDs are left free in the main emission direction in order to avoid undesired color influences due to media changes.

The circuit board 2 with the pre-fixed electrical components 3 is glued to the cover 5 after the fixing adhesive 9 has cured. Here, an adhesive channel K between the circuit board 2 and the cover 5 is completely filled with the UV adhesive 8 and then cured through the translucent circuit board 2 by means of a UV lamp. This form of gluing means that the shear forces no longer act directly on the individual electrical components 3, but on the entire pre-fixing of all components involved. The electrical components 3 thus stick to the conductor tracks 4 and the component 1 produced by means of this method also meets the required framework conditions of environmental influences.

The electrical components 3 can be pre-fixed on the printed circuit board 2 at points, as shown in FIG. 2, or flat, as shown in FIG. The selective pre-fixing of the electrical components 3 can be implemented in a very space-saving manner and with little material, in particular fixing adhesive 9, and with little effort. With this pre-fixing at specific points, the electrical components 3 are only fixed at their sides on the printed circuit board 2 at specific points. This punctual pre-fixation is, however, significantly weaker than the flat pre-fixation.

During the two-dimensional pre-fixing, the electrical components 3, advantageously including the conductor tracks 4, in particular made of silver, are enclosed with the fixing adhesive 9. Depending on the electrical component 3, in particular with the LEDs, it may be necessary to leave the respective electrical component 3 free at the top and only on all sides, i. H. on the circumferential side, to be attached to the circuit board 2. This flat pre-fixation is significantly more stable than the selective pre-fixation.

FIG. 1 shows an embodiment of the component 1 without pre-fixing by means of the fixing adhesive 9 and without gluing by means of the UV adhesive 8, as a result of which no environmentally stable gluing is achieved. As shown on the basis of the further embodiment of the component 1 in FIG. 4, in contrast to this first embodiment of the component 1 shown in FIG Prefixed punctually or flatly on the circuit board 2, in particular by means of the fixing adhesive 9. This pre-fixing, d. H. the fixing adhesive 9, hardened.

The entire printed circuit board 2 is then advantageously plasma-treated, in particular shortly before the complete gluing by means of the UV adhesive 8, in particular also a surface of the LEDs. This is done in order to avoid delamination of the UV adhesive 8 from silicone encapsulation of the LEDs and the resulting formation of air bubbles above the LEDs, since this would result in a change of media and thus a color inhomogeneity of the light emitted by the LEDs. The plasma treatment improves the adhesion, in particular of the silicone potting surface of the LEDs, for the UV adhesive 8.

In one possible embodiment of the method, the reflector film 6 is also plasma-treated in order to achieve better adhesion of the UV adhesive 8. The printed circuit board 2 with the pre-fixed electrical components 3 is then glued to the cover 5. Here, the cover 5 with the reflector film 6 already arranged therein is placed on the circuit board 2 and, as already described above, the adhesive channel K between the circuit board 2 and the cover 5 is completely filled with the UV adhesive 8 and then through the translucent circuit board 2 cured through using a UV lamp.

The adhesive tape 7 can, for example, already at the beginning, i. H. already before the process steps described, or for example at the end, d. H. be applied to the underside of the printed circuit board 2 after the process steps described or, for example, during the process sequence described.

For an electrical energy supply, in particular the LEDs 3, it is necessary to make electrically conductive contact with the conductor tracks 4 on the circuit board 2 with at least one electrical cable 10. This contact point must be designed in such a way that it can withstand environmental influences, for example temperatures from -30 ° C. to 90 ° C., without this contact point being damaged and the contact becoming detached.

A holding force of the connection of the cable 10 to the conductor tracks 4 must, for example, withstand tensile forces of at least 40 N to 50 N and advantageously only fail after the circuit board 2. The problem here is that there is a risk that the contact will become loose due to temperature interactions and environmental influences. Due to the different thermal expansion coefficients of the materials used and a low connection force to the conductor tracks 4, a thermally induced movement is sufficient, for example, to separate the connection and lead to errors in the contacting.

In order to avoid this and to create electrically conductive contacting of the circuit board 2 that is stable against environmental influences, as shown in FIG is, a contact pin 11 advantageously made of brass, also referred to as a brass pin, is pressed into a fit of the circuit board 2, in particular in a form-fitting manner, and is sunk into a groove-like recess 12 made in the circuit board 2, in particular milled, until a Collar formation 13 rests against a front end of the contact pin 11 on a bottom of the groove-like recess 12. I. E. the contact pin 11 is pressed into the circuit board 3 from a flat side, in particular the upper side, in the direction of an opposite flat side, in particular the underside, penetrating, in particular positively, until the collar formation 13 rests on the bottom of the groove-like recess 12.

The printed circuit board 2 is then printed with the conductor tracks 4 and the groove-like recess 12 is completely filled, in particular with silver conductor track paste. The front end of the contact pin 11 with the collar formation 13 is thus advantageously covered with the conductor track 4, in particular made of silver, which is printed in the groove-like recess 12. The collar formation 13 of the contact pin 11 thus prevents the contact pin 11 from moving out of the circuit board 2, since one contact side of it now rests on the bottom of the groove-like recess 12, which prevents it from being pushed completely through the circuit board 2, and the opposite contact side with it the conductor track 4 is covered, so that a pushing back of the contact pin 11 is prevented. The contact pin 11 is thus securely anchored in the circuit board 2.

The printed circuit board 2 can then, for example, be completely processed, equipped and, in the example described here, to form the component 1, can be glued to the cover 5 in the manner described above.

For electrically conductive contacting of this contact pin 11 and thus the circuit board 2, in particular the conductor tracks 4 and thus in particular the LEDs 3, a crimp sleeve 14 is crimped with the contact pin 11. Starting from the side facing away from the contact pin 11, the cable 10, advantageously with a cable end sleeve 15, is inserted into this crimp sleeve 14, electrically conductively contacted with the contact pin 11 and crimped to the crimp sleeve 14. The electrically conductive contact between the cable 10 and the contact pin 11 can take place through direct electrically conductive contact between the cable 10, in particular the cable end sleeve 15, with the contact pin 11 and / or via the crimp sleeve 14.

In order to protect the connection produced in this way, in particular the electrically conductive contact, against moisture, a shrink tube is then used 16 drawn and shrunk over the entire connection, ie in particular over the contact pin 11, the crimp sleeve 14 and at least in sections over the cable 10, in particular over the cable end sleeve 15.

The crimping of the crimp sleeve 14 with the contact pin 11 takes place in particular in such a way that the contact pin 11 is locked in its position in the printed circuit board 2 by the crimp sleeve 14, with the crimp sleeve 14 in particular advantageously preventing the contact pin 11 from moving in the longitudinal direction of the contact pin 11 . For this purpose, the crimp sleeve 14 is advantageously crimped to the contact pin 11, as shown in FIG.

The crimp sleeve 14 thus fulfills a locking function for the contact pin 11 and in particular prevents the contact pin 11 from being pushed back against the press-in direction, which in particular keeps the contact pin 11 in contact with conductive pastes and / or with the conductor track 7 at the end of the contact pin 11.

This form of connection, in particular the electrically conductive contact, enables electrically conductive contact to be made between the conductor tracks 4, which are in particular made of silver, of the circuit board 2 with regular electrical cables 10, which can withstand temperature and environmental influences. In addition, a simple and, in particular, initially still wireless handling of the component 1 is thereby made possible, i. H. in particular a cordless production, the electrical cables 10 then being connected, for example, only at the end, for example at the end of the production or during the assembly of the component 1, in particular on the vehicle.

FIG. 6 shows a schematic representation of this electrical assembly 17 in a top view, only a section of this electrical assembly 17 being shown here for reasons of simplified and clear representation. The electrical components 3 can be a plurality of LEDs 18 and a plurality of electrical series resistors 19.

The LEDs 18 and electrical series resistors 19 are divided into several component groups 20, the LEDs 18 and electrical series resistors 19 each Component group 20 are electrically connected in series and the component groups 20 are electrically connected in parallel to one another. Electrical contacting of the LEDs 18 and the electrical series resistors 19 takes place via conductor tracks 4, which are designed as screen-printed silver conductor tracks on the circuit board 2.

The assembly 17 is part of a component 1 as shown in FIG. 1 and explained above.

With a conventional design of the electrical assembly 17, for example with an arrangement of the LEDs 18 in groups of two and three, each with an electrical series resistor 19, which is designed for an effective voltage of 10 V, this would result in prescribed electrical load tests, for example in the case of a transient overvoltage of 17 V for 200 minutes, individual LED groups fail due to massive heat development of individual electrical series resistors 19, which melt into the circuit board 2 made of thermoplastic material and cut through the printed silver conductor tracks. In addition, a heat development of the conductor tracks 4 would take place asymmetrically and especially in the area of an electrical voltage feed.

The overheating of the electrical series resistors 19 results from the fact that in the application of the illuminated emblem described here, in particular the illuminated brand emblem intended for attachment to the vehicle, there is no possibility of cooling the electrical assembly 17, in particular the printed circuit board 2, using conventional cooling concepts. In particular, no cooling is possible by supplying air, by means of cooling segments or by transporting heat to the outside. In particular in the event of an electrical overvoltage, the electrical series resistors 19 overheat, since this electrical overvoltage drops across the electrical series resistors 19.

The asymmetrical heat distribution results from a drop in resistance that cannot be neglected in the printed silver conductor tracks, even over short distances. In this case, the electrical resistance that drops across the conductor tracks 4 increases with increasing distance from the electrical voltage feed. This electrical resistance, which drops at the conductor tracks 4, does not load the respective electrical series resistor 19, but rather the one even in the event of an overvoltage Conductor tracks 4. As a side effect, the various electrical voltages resulting therefrom also have a negative effect on a light image generated by the LEDs 18.

In order to solve these problems and to implement a thermally stable electrical circuit on the printed circuit board 2 and thus a thermally stable electrical assembly 17 for the component 1 without using additional cooling concepts, thermal management and thermal optimizations are provided of the example shown schematically in FIG. 6.

In the solution described here, it is provided that the component groups 20, which are electrically connected in parallel to one another, each have the same number of LEDs 18, in the example shown, two LEDs 18 each, which are electrically connected in series. Furthermore, the component groups 20 are designed for higher electrical voltages. In particular, oversized electrical series resistors 19 are used for this purpose. In particular, a resistance value of the electrical series resistors 19 of the respective component group 20 is required to be higher than for a permissible current flow through the LEDs 18 of the respective component group 20. As a result, even with a normal electrical voltage, more electrical voltage drops across the series resistors 19, but the higher series resistors 19 withstand greater loads without overheating.

Furthermore, the electrical series resistors 19 are divided, i. H. In the respective component group 20, there is not a single large electrical series resistor 19, but rather several small electrical series resistors 19 which are electrically connected in series with one another and with the LEDs 18 of their component group 20.

It is provided that the electrical series resistors 19 are advantageously arranged between the LEDs 18, ie an electrical series resistor 19 and an LED 18 are arranged alternately one after the other in the respective component group 20, as shown in FIG. As already described, two LEDs 18 and thus also two electrical series resistors 19, which are electrically connected in series, are provided here for each component group 20. Thus, in the respective component group 20, an electrical series resistor 19, then an LED 18, then again an electrical series resistor 19 and then again an LED 18 are arranged and electrically connected in series. Electrotechnically, this division of the electrical series resistors 19 does not result in any relevant difference, but it achieves an optimized heat distribution by avoiding a few strong local heating points and instead achieving several heating points distributed over a larger area on the circuit board 2 with less heating. I. E. This solution results in a better distribution of the heating series resistors 19 on the printed circuit board 2, which avoids excessive heating of the printed circuit board 2 at a few points due to a few large electrical series resistors 19 and instead an areally distributed lower heating of the printed circuit board 2 at many points many smaller electrical series resistances 19 is achieved, which does not damage the circuit board 2 and the conductor tracks 4.

Advantageously, the printed conductor tracks 4 are also designed with different thicknesses in order to make the portion of the electrical voltage that drops across the conductor tracks 4 more constant. In particular, the conductor tracks 4 are made thicker, in particular wider, in the area of the electrical voltage introduction and are made increasingly thinner, in particular narrower, with increasing distance from the electrical voltage introduction.

In the case of series-connected component groups, it can also be useful to make the conductor tracks further away from the voltage introduction point thicker, i.e. wider, in order to adequately supply component groups further away from the voltage introduction point with current.

In this solution, the electrical circuit is thus optimized with regard to thermal management, in particular through the variable conductor track thickness and active heat dissipation through the design and positioning of the electrical series resistors 19 described.

Examples of the invention are briefly listed below:

1. Example of a method for producing a component (1) which comprises a printed circuit board (2) and a plurality of electrical components (3) arranged thereon, wherein the electrical components (3) are pre-fixed on the printed circuit board (2) made of plastic by means of a fixing adhesive (9) and then completely encapsulated with a UV adhesive (8). Method according to Example 1, wherein an emblem is formed, the printed circuit board (2) made of polymethyl methacrylate being connected to a chrome-plated cover (5) made of polycarbonate and / or acrylonitrile-butadiene-styrene. Method according to example 2, wherein the circuit board (2) is glued to the chrome-plated cover (5) by completely filling an adhesive channel (K) between the circuit board (2) and the chrome-plated cover (5) with the UV adhesive (8) and the UV adhesive (8) is then irradiated through the translucent printed circuit board (2) by means of a UV lamp and thereby cured. Method according to one of the preceding examples, wherein the fixing adhesive (9) for pre-fixing the electrical components (3) by means of a valve on a mounting device, by means of which the electrical components (3) are applied to the circuit board (2), at least in sections on the circuit board (2) and the electrical components (3) is applied. Example of an electrical assembly (17), comprising a printed circuit board (2) and a plurality of LEDs (18) arranged thereon, wherein

- The circuit board (2) is made of plastic,

- The LEDs (18) are divided into several component groups (20), the LEDs (18) of each component group (20) being connected electrically in series and the component groups (20) being connected electrically in parallel to one another, each component group (20) having one A plurality of electrical series resistors (5) which are electrically connected in series with the LEDs (18) of the respective component group (20), an electrical series resistor (19) and at least one LED (18) being arranged alternately one after the other,

- A resistance value of the electrical series resistors (19) of the respective component group (20) is higher than for a permissible current flow through the LEDs (18) of the respective component group (20) are required, and conductor tracks (4) on the circuit board (2) have different thicknesses at different positions on the circuit board (2). Electrical assembly (17) according to example 5, wherein the conductor tracks (4) are designed as silver conductor tracks by means of screen printing. Electrical assembly (17) according to example 4 or 5, the component groups (20) each having two LEDs (18). Electrical assembly (17) according to one of Examples 4 to 6, the component groups (20) each having two electrical series resistors (19). Example of a method for electrically conductive contacting of a printed circuit board (2), in particular in combination with a method according to Examples 1 to 4, a contact pin (11) made of brass penetrating the printed circuit board (2) and positively pressed into the printed circuit board (2), until a collar formation (13) rests on a front end of the contact pin (5) on a bottom of a groove-like recess (12) in the circuit board (2), this front end with a conductor track (4) printed in the groove-like recess (12) made of silver, the contact pin (11) being crimped with a crimp sleeve (14), an electrical cable (10) being inserted into the crimp sleeve (14), electrically conductive contact with the contact pin (11) and with the crimp sleeve (14 ) is crimped, and a shrink tube (16) is arranged over the contact pin (11), the crimp sleeve (14) and at least in sections over the electrical cable (10). Method according to Example 9, wherein the electrical cable (10) is inserted into the crimp sleeve (14) with a cable end sleeve (15) arranged thereon.

Method according to Example 9 or 10, wherein the circuit board (2) is populated before the contact pin (11) with the Crimping sleeve (14) is crimped. Method according to one of Examples 10 or 11, wherein the circuit board (2) is glued to at least one other component before the contact pin (11) is crimped with the crimp sleeve (14).

List of reference symbols

1 component

Circuit board electrical component

Track

cover

Reflector foil

duct tape

8 UV adhesive

9 fixing adhesive

10 cables

11 contact pin

12 deepening

13 Collar molding

14 crimp barrel

15 cable end sleeve

16 heat shrink tubing

17 assembly

18 LEDs

19 series resistor

20 component group

K adhesive channel

S beam of light

Claims

1. A method for producing a component (1) which comprises a printed circuit board (2) and a plurality of electrical components (3) arranged thereon, characterized in that the electrical components (3) on the plastic printed circuit board (2) by means of a Fixing adhesive (9) are pre-fixed and then completely potted with a UV adhesive (8).

2. The method according to claim 1, characterized in that an emblem is formed, the printed circuit board (2) made of polymethyl methacrylate being connected to a chrome-plated cover (5) made of polycarbonate and / or acrylonitrile-butadiene-styrene.

3. The method according to claim 2, characterized in that the circuit board (2) is glued to the chrome-plated cover (5) by an adhesive channel (K) between the circuit board (2) and the chrome-plated cover (5) completely with the UV Adhesive (8) is filled and the UV adhesive (8) is then irradiated through the translucent circuit board (2) by means of a UV lamp and thereby cured.

4. The method according to any one of the preceding claims, characterized in that the fixing adhesive (9) for pre-fixing the electrical components (3) by means of a valve on a mounting device, by means of which the electrical components (3) are applied to the circuit board (2), is applied at least in sections to the circuit board (2) and the electrical components (3).

5. The method according to any one of claims 1 to 4, characterized in that a moisture-curing adhesive is used as the UV adhesive (8).

6. Electrical assembly (17), comprising a printed circuit board (2) and a plurality of LEDs (18) arranged thereon, characterized in that

- The circuit board (2) is made of plastic,

- The LEDs (18) are divided into several component groups (20), the LEDs (18) of each component group (20) being connected electrically in series and the component groups (20) being connected electrically in parallel to one another, each component group (20) having one A plurality of electrical series resistors (19) which are electrically connected in series with the LEDs (18) of the respective component group (20), an electrical series resistor (19) and at least one LED (18) being arranged alternately one after the other.

7. Electrical assembly according to claim 6, characterized in that

- A resistance value of the electrical series resistors (19) of the respective component group (20) is higher than required for a permissible current flow through the LEDs (18) of the respective component group (20), and / or

- Conductor tracks (4) on the circuit board (3) at different positions on the circuit board (3) have a different thickness.

8. Electrical assembly (2) according to claim 6 or 7, characterized in that the conductor tracks (4) are designed as silver conductor tracks by means of screen printing.

9. Electrical assembly (2) according to one of claims 6 to 8, characterized in that the component groups (20) each have two LEDs (18).

10. Electrical assembly (2) according to one of claims 6 to 9, characterized in that the component groups (20) each have two electrical series resistors (19).

11. A method for electrically conductive contacting of the circuit board (2) of the component produced by the method according to claims 1 to 5 and / or the component according to one of claims 6 to 10, characterized in that a contact pin (11) made of brass, the circuit board (2) is pressed penetratingly into the circuit board (2) with a positive fit until a collar formation (13) on a front end of the contact pin (5) rests on a bottom of a groove-like recess (12) in the circuit board (2), this front end is covered with a printed conductor (4) made of silver in the groove-like recess (12), the contact pin (11) being crimped with a crimp sleeve (14), an electrical cable (10) being inserted into the crimp sleeve (14) with electrically conductive contact is made with the contact pin (11) and is crimped to the crimp sleeve (14), and over the contact pin (11), the crimp sleeve (14) and at least in sections over the electrical Cable (10) a shrink tube (16) is arranged.

12. The method according to claim 11, wherein the electrical cable (10) with a cable end sleeve (15) arranged thereon is inserted into the crimp sleeve (14).

13. The method according to claim 11 or 12, wherein the circuit board (2) is populated before the contact pin (11) is crimped with the crimp sleeve (14).

14. The method according to any one of claims 11 to 13, wherein the circuit board (2) is glued to at least one other component before the contact pin (11) is crimped with the crimp sleeve (14).