DE102010043788B4 - Circuit arrangement for operating at least one light source and method for producing such a circuit arrangement - Google Patents

Abstract

Circuit arrangement for operating at least one light source with at least one metal core board, which has a layer structure with at least one metal core, a first insulation layer, which is coupled to a first side of the metal core, and a first conductor layer, which is connected to the side of the first insulation layer facing away from the metal core is coupled; - a plurality of contact pads arranged on the first conductor layer; and - at least one light source coupled to at least two of the plurality of contact pads;characterized in that the circuit arrangement further comprises a de-braiding board (10), the de-braiding board (10) having an insulator core (12), a first conductor layer (14), which is coupled to a first side of the insulator core (12), and a second conductor layer (16) which is coupled to a second side of the insulator core (12), wherein on the first (14) and the second conductor layer (16) a plurality of contact pads are provided on the disentanglement board (10), at least one contact pad (18) of the first conductor layer (14) of the disentanglement board (10) being coupled to one another by a common soldering point with at least one contact pad of the first conductor layer of the metal core board.

Description

Technical area

The present invention relates to a circuit arrangement for operating at least one light source with at least one metal core board, which has a layer structure with at least one metal core, a first insulation layer, which is coupled to a first side of the metal core, and a first conductor layer, which is facing away from the metal core Side of the first insulation layer is coupled, a plurality of contact pads arranged on the first conductor layer, and at least one light source that is coupled to at least two of the plurality of contact pads. It also relates to a method for producing such a circuit arrangement.

State of the art

In the following example, high-performance light-emitting diodes in SMD design are used as the light source for a better understanding of the invention. As will become clear from the following statements, the present invention can also be used advantageously with other types of light sources.

High-performance light-emitting diodes in SMD design are usually mounted on circuit boards with a metal core, so-called metal core boards, to ensure suitable heat dissipation. Metal core boards can only be equipped with more than one conductor track level (routing layer) with great effort. As a rule, there is only one level on the assembly side, the so-called top layer. If the number of mounted LEDs increases and additional, complex components, such as power drivers, need to be mounted, the board can no longer be unbundled without additional measures.

For unbundling, bridges in the form of 0 ohm resistors often have to be inserted to ensure line crossing. Each bridge requires its own component and therefore requires a corresponding amount of material and time. A well-known example of such a circuit arrangement is an LED module known under the name DRAGONchain in the Colormix version for realizing colored RGB effect light. This can be used to create intense color effects and special atmospheres. Thanks to the side-emitting light, even large areas can be backlit efficiently and homogeneously with just a few modules. Such an LED module consists of a metal core board with 24 Golden DRAGON high-performance LEDs and a designer heat sink. The heart of the RGB light chain are six metal core boards, each with four Golden DRAGON Argus LEDs.

However, a total of 49 0-Ohm bridges must be provided on all boards together and 11 on individual boards alone. Since the power drivers are color-specific, cables must be pulled through from the first to the last board. Driver components are distributed across six boards. The provision of 0 ohm bridges results in a lot of effort and therefore in undesirably high manufacturing costs.

As an alternative, it is known, for example in a dimmer with the name Osram Optotronic OT DMX2CC, to provide metal core boards with several layers. However, these have worsened thermal properties and require special drilling and assembly techniques to produce the vias.

The DE 693 29 542 T2 discloses a metallic motherboard used for assembling electronic components. The board is formed by laminating multiple copper foils onto a metallic board using thermoplastic polyimide. Circuit patterns are formed on the copper foils. The metallic base plate with such circuit patterns is bent and deep drawn to form a box with an open surface. The area of the open area is almost equal to the area of the ground area. Flanges are formed on the edges of the open area. The flanges are patterned to form lines that are used to connect this board to another circuit board. The three-dimensional circuit board prepared in this way is mounted on another circuit board with the open side facing down. The leads are soldered to the circuit pattern on the circuit board. Electronic components are mounted on the underside of the three-dimensional circuit board.

The US 5,488,256 A discloses a hybrid IC with a metal base, a control element interconnection substrate with a thin wiring pattern, and a power element interconnection substrate with a thick wiring pattern. The connection substrates are mounted on the metal base. Extensions protrude from the wiring pattern on the interconnection substrate to electrically connect the interconnection substrate to the interconnection substrate.

The DE 44 22 216 A1 discloses a metallic circuit board formed by laminating an insulating layer on the surface of a metallic board as a base and then mounting electronic parts on the surface of the Insulation layer formed line arrangement is formed. A double-sided circuit board with electronic parts mounted on it is placed parallel to it. Both of the circuit boards are monolithically supported and secured by filling the space between the circuit boards with an insulating resin and then curing the resin. Further, an insulating resin is laminated on the surface of the circuit board in such a manner that the resin can cover the mounted electronic parts, and then cured.

Presentation of the invention

The object of the present invention is therefore to develop a generic circuit arrangement in such a way that a reduction in manufacturing costs is made possible even when a large number of light sources and/or complex components are installed. The task also consists of providing a method for producing such a circuit arrangement.

These tasks are solved by a circuit arrangement with the features of patent claim 1 and by a method with the features of patent claim 19.

The present invention is based on the knowledge that a large proportion of the manufacturing costs arise from the effort required in the prior art to unbundle the circuit board. In order to reduce the cost of unbundling, a unbundling board is therefore further provided according to the invention, wherein the unbundling board comprises an insulator core, a first conductor layer, which is coupled to a first side of the insulator core, and a second conductor layer, which is coupled to a second side of the insulator core. A plurality of contact pads are provided on the first and second conductor layers of the disentanglement board, with at least one contact pad of the first conductor layer of the disentanglement board being coupled to one another by a common soldering point with at least one contact pad of the first conductor layer of the metal core board.

In this way, the unbundling problem can be transferred to the unbundling board, which is firmly connected to the metal core board through the common soldering point. This means that the excellent thermal and electrical properties of a single-layer metal core board are retained and the assembly effort and space required for 0-ohm bridges is reduced. For a given number of conductors, the unbundling problem can be concentrated on a defined, spatially limited location on the metal core board.

Preferably, the at least one contact pad of the first conductor layer of the disentanglement board and the at least one contact pad of the first conductor layer of the metal core board are electrically insulated on the respective conductor layer. They are therefore used exclusively for the stationary attachment of the disentanglement board to the metal core board.

Preferably, the unbundling board comprises a matrix of wiring rows and wiring columns, the wiring rows being arranged on a first of the two conductor layers and the wiring columns being arranged on the second of the two conductor layers. This generally opens up the possibility of electrically connecting any wiring row to any wiring column.

Furthermore, the disentangling board includes through-connections through the insulator layer of the disentangling board, with each intersection of wiring rows with wiring columns being assigned such a through-plating. In other words, a large number of 0-Ohm bridges are essentially combined into a single component. A metal core board with multiple conductor track levels is therefore no longer necessary. This also eliminates the need to separately install a large number of 0-ohm bridges. The unbundling problem is concentrated at one point on the metal core board for a given number of conductors.

Each plated-through hole is preferably assigned a first and a second inner contact pad on the same conductor layer of the disentanglement board, the first inner contact pad being electrically conductively coupled to the assigned wiring row and the second inner contact pad being electrically conductively coupled to the assigned wiring column. The first inner contact pad and the second inner contact pad are preferably arranged relative to one another in such a way that they are electrically insulated from one another in a first state. The first inner and the second inner contact pad can be connected to one another in an electrically conductive manner to produce a second state.

To produce an electrically conductive connection between the first and the second inner contact pad, a third contact pad is preferably provided on the first conductor layer of the metal core board, which is assigned to the first and the second inner contact pad. The third contact pad is preferably designed in such a way that it can be electrically conductively connected to the first and second inner contact pads by a soldering process. This reduces the effort required for unbundling to simply placing pads on the metal core board for the connection of wiring rows and wiring columns of the disentanglement board matrix. The complexity of this problem is so small that even an inexperienced user can solve it mentally within seconds. For unbundling boards with a large number of wiring rows and wiring columns, algorithms can be provided that automate the unbundling.

The unbundling board is preferably designed as an FR4 board. The coefficient of thermal expansion of the material used for the unbundling board is preferably adapted to the coefficient of thermal expansion of the metal core board, for example aluminum. This can prevent the unbundling board from breaking off when the composite of the metal core board and the unbundling board heats up.

Each wiring row and each wiring column is preferably connected to at least one outer contact pad on the disentanglement board, with corresponding contact pads on the first conductor layer of the metal core board being assigned to at least two of these outer contact pads in order to produce an electrically conductive connection. The wiring rows and wiring columns are initially independent of one another, but can be linked in an electrically conductive manner via a pad, in particular the third contact pad. In particular, two adjacent inner contact pads of the disentanglement board are electrically linked to one another by the third contact pad during the soldering process. A matrix of rows and columns is created, which are linked to the circuits of the metal core board and to each other by inserting the third contact pads on the metal core board. The signals to be unbundled are connected to the outer contact pads of the unbundling board in such a way that they no longer cross each other in the circuit diagram of the supporting metal core board. For unbundling purposes, each signal to be unbundled is led into the unbundling board at an external contact pad and out again at another external contact pad. A component for unbundling five signals, for example, requires ten external connections in the form of ten external contact pads. One half of these connections are now coupled to each wiring line in the unbundling board. The other half is coupled to each wiring column. In the example, five conductor tracks run in a first direction and five conductor tracks run orthogonally in a second direction. Each row of wiring crosses each column of wiring. An electrically conductive connection from intersecting conductor tracks to the two assigned outer contact pads can be established via the plated-through holes mentioned at the crossing points.

Although the contacting of two adjacent inner contact pads can be created by any bridge, it is preferred to do this via a third contact pad of the metal core board, already mentioned above, which covers the two inner contact pads of the disentanglement board. This means that no additional conductor tracks are necessary on the metal core board. A link can thus be established between any wiring rows and wiring columns of the disentanglement board by using a contact pad on the metal core board that is not further linked there to link two adjacent inner contact pads of the disentanglement board.

According to a preferred development, further contact pads are provided at least on one of the conductor layers of the disentanglement board, in particular on the conductor layer that faces away from the metal core board. These further contact pads can be arranged in such a way that further components, in particular SMD components, can be braided in. In addition to improved separation, this enables the arrangement of the other components in a very small space on another level. These other components then have a lower temperature level because the non-metallic separation component conducts heat more poorly than the metal core board. This allows the service life of sensitive components in complex circuits to be extended. In particular, driver components and capacitors can be operated at a separate temperature level.

Even more complex and dense unbundling can be achieved if the unbundling board is implemented with more than two levels.

As already mentioned, the at least one light source can be an LED, in particular a high-performance LED.

The disentanglement board can further comprise a layer structure with at least three conductor layers, with an insulator layer being arranged between each two conductor layers. In this context, the wiring rows and the wiring columns can be arranged on a conductor layer which is surrounded on both sides by an insulator layer. This makes it possible to achieve increased dielectric strength between the conductor tracks of the unbundling board and the metal core board, since in this way the wiring levels of the unbundling board are laid in inner board layers. Compared to the case in which only soldering varnish is used for insulation, increased dielectric strength and significantly improved tracking current resistance can be achieved because the conductor tracks are surrounded on all sides by an insulator whose insulation properties are significantly increased compared to solder mask.

According to a further preferred embodiment, the surface of the disentanglement board facing the metal core board has at least one groove for discharging gas. This measure takes into account the fact that when soldering in the reflow process, increased gas development under the disentangling board may have to be taken into account. If, as mentioned, the wiring is carried out in the inner layers of the unbundling board, at least one such groove for discharging gas can be provided by scoring the underside of the unbundling board using a milling cutter in one direction without affecting the function of the unbundling board.

Alternatively, the disentangling board can comprise a through hole for discharging gases, the through hole preferably being provided by the contact pad on the first conductor layer of the disentangling board, which is coupled to one another by a common soldering point with at least one contact pad of the first conductor layer of the metal core board. This can also reliably prevent the disentanglement board from breaking off from the metal core board.

Further advantageous embodiments result from the subclaims.

The preferred embodiments presented with reference to the circuit arrangement according to the invention and their advantages apply accordingly, as far as applicable, to the method according to the invention.

Short description of the drawing(s)

• 1 zeigt in schematischer perspektivischer Darstellung ein Ausführungsbeispiel einer Entflechtungsplatine, wobei zur Erleichterung des Verständnisses das Platinenmaterial der Entflechtungsplatine durchsichtig dargestellt ist.

An exemplary embodiment of the present invention is described in more detail below with reference to the accompanying drawing.

• 1 shows a schematic perspective view of an exemplary embodiment of a disentanglement board, with the board material of the disentanglement board being shown transparent to make it easier to understand.

Preferred embodiment of the invention

1 shows a schematic representation of an exemplary embodiment of a disentanglement board 10, which is firmly connected to a metal core board of the circuit arrangement in order to produce a circuit arrangement according to the invention. The metal core board is omitted to increase clarity. To make it easier to understand, the unbundling board is also shown transparently. It includes an insulator core 12 and a first conductor layer 14, which is coupled to a first side of the insulator core 12, and a second conductor layer 16, which is coupled to a second side of the insulator core 12.

The attachment of the disentanglement board 10 to the metal core board is preferably carried out by contact pads of the first conductor layer 14 of the disentanglement board 10, which are coupled to a contact pad of the first conductor layer of the metal core board by a common soldering point. Such a contact pad is preferably electrically insulated both on the first conductor layer 14 of the disentanglement board 10 and the corresponding contact pad on the first conductor layer of the metal core board. A contact pad 18 is shown as an example, and several such contact pads 18 can be provided on the disentanglement board for a secure hold, but are shown in the illustration 1 are not shown for the sake of clarity.

A matrix of wiring rows Z1 to Zn and wiring columns S1 to Sn is provided on the disentanglement board 10, where n was chosen to be 5 in the example. The wiring rows Z1 to Zn are arranged on the conductor layer 16 of the unbundling board 10, while the wiring columns S1 to Sn are arranged on the conductor layer 14 of the unbundling board 10. Each crossing point of wiring rows Z1 to Zn and wiring columns S1 to Sn is assigned vias D11, D12, Dnn through the insulator layer 12 of the disentanglement board 10. Each plated-through hole D11, D12, Dnn is assigned a first inner contact pad IKZ1S1 and a second inner contact pad IKS1Z1 on the same conductor layer, in this case the conductor layer 14 of the disentanglement board 10, the first inner contact pad IKZ1S1 with the assigned wiring line Z1 and the second inner contact pad IKS1Z1 is conductively coupled to the associated wiring column S1. For the sake of clarity, only the inner contact pads for the intersection point S1, Z1 are in the 1 provided with reference numbers.

First, the first inner contact pad IKZ1S1 and the second inner contact pad IKS1Z1 are electrically insulated from each other. By placing a third contact pad, which is preferably provided on the first conductor layer of the metal core board and is assigned to the first inner contact pad IKZ1S1 and the second inner contact pad IKS1Z1, the first inner contact pad IKZ1S1 and the second inner contact pad IKS1Z1 can be electrically connected to one another. This happens in particular through a soldering process.

Each line of wiring is connected to an external contact pad AKZ1, AKZn. Each wiring column is connected to an external contact pad AKS1, AKSn. If, for example, the inner contact pad IKZ1S1 is electrically conductively connected to the inner contact pad IKS1Z1, an electrically conductive connection is obtained between the outer contact pad AKS1 and the outer contact pad AKZ1. By appropriately connecting the outer contact pad AKS1 to a contact pad on the metal core board and the outer contact pad AKZ1 to another contact pad on the metal core board, a conductive connection can be established between these two contact pads on the metal core board.

If further inner contact pads are connected to one another in an electrically conductive manner and electrically conductive connections are made to other contact pads on the metal core board on the associated outer contact pads, these signals can be easily unbundled using the unbundling board 10 shown. Further contact pads can be provided on the conductor layers 14, 16 of the disentanglement board 10, so that further components, in particular SMD components, can be braided in.

The unbundling board 10 is preferably designed as an FR4 board. In an exemplary embodiment not shown, the disentanglement board 10 may comprise a layer structure with at least three conductor layers, with an insulator layer being arranged between each two conductor layers. The wiring rows and wiring columns are then preferably arranged on a conductor layer which is surrounded on both sides by an insulator layer.

On the surface facing the metal core board, a groove 20 for discharging gas may be provided. A through hole 22 can also be provided for discharging gases, the through hole 22 preferably being provided by the at least one contact pad 18 on the disentangling board 10, which is coupled to one another by a common soldering point with at least one contact pad of the first conductor layer of the metal core board.

Claims (19)

Circuit arrangement for operating at least one light source with - at least one metal core board, which has a layer structure with at least one metal core, a first insulation layer, which is coupled to a first side of the metal core, and a first conductor layer, which is connected to the side of the first insulation layer facing away from the metal core is coupled; - a plurality of contact pads arranged on the first conductor layer; and - at least one light source coupled to at least two of the plurality of contact pads; characterized in that the circuit arrangement further comprises an unbundling board (10), the unbundling board (10) having an insulator core (12), a first conductor layer (14) coupled to a first side of the insulator core (12), and a second conductor layer (16), which is coupled to a second side of the insulator core (12), wherein a plurality of contact pads are provided on the first (14) and the second conductor layer (16) of the disentangling board (10), wherein at least one contact pad ( 18) the first conductor layer (14) of the disentanglement board (10) are coupled to one another with at least one contact pad of the first conductor layer of the metal core board by a common soldering point. Circuit arrangement according to Claim 1 , characterized in that the at least one contact pad (18) of the first conductor layer (14) of the disentanglement board (10) and the at least one contact pad of the first conductor layer of the metal core board are electrically insulated on the respective conductor layer (14, 16). Circuit arrangement according to one of the Claims 1 or 2 , characterized in that the unbundling board (10) comprises a matrix of wiring rows (Z1, Zn) and wiring columns (S1, Sn), the wiring rows (Z1, Zn) on the first (14) of the two conductor layers (14, 16) and the wiring columns (S1, Sn) are arranged on the second (16) of the two conductor layers (14, 16). Circuit arrangement according to Claim 3 , characterized in that the disentanglement board (10) comprises plated-through holes (D11, Dnn) through the insulator layer of the disentanglement board (10), each intersection point (Z1, S1; Zn, Sn) of wiring rows (Z1, Zn) having wiring columns (S1, Sn) is assigned such a via (D11, Dnn). Circuit arrangement according to Claim 4 , characterized in that each plated-through hole (D11, Dnn) is assigned a first (IKZ1S1) and a second inner contact pad (IKS1Z1) on the same conductor layer (14; 16) of the disentanglement board (10), the first inner contact pad (IKZ1S1). the assigned wiring row (Z1) and the second inner contact pad (IKS1Z1) are electrically conductively coupled to the assigned wiring column (S1). Circuit arrangement according to Claim 5 , characterized in that the first inner contact pad (IKZ1S1) and the second inner contact pad (IKS1Z1) are arranged relative to one another in such a way that they are electrically insulated from one another in a first state. Circuit arrangement according to Claim 6 , characterized in that the first inner (IKZ1S1) and the second inner contact pad (IKS1Z1) can be electrically conductively connected to one another to produce a second state. Circuit arrangement according to one of the Claim 6 or 7 , characterized in that in order to produce an electrically conductive connection between the first (IKZ1S1) and the second inner contact pad (IKS1Z1), a third contact pad is provided on the first conductor layer of the metal core board, which corresponds to the first (IKZ1S1) and the second inner contact pad (IKS1Z1 ) assigned. Circuit arrangement according to Claim 8 , characterized in that the third contact pad is designed such that it can be electrically conductively connected to the first (IKZ1S1) and the second inner contact pad (IKS1Z1) by a soldering process. Circuit arrangement according to one of the Claims 3 until 9 , characterized in that each wiring row (Z1, Zn) and each wiring column (S1, Sn) is connected to at least one outer contact pad (AKS1, AKSn, AKZ1, AKZn) on the unbundling board (10), thereby producing an electrically conductive Connection at least two of these outer contact pads corresponding contact pads are assigned to the first conductor layer of the metal core board. Circuit arrangement according to one of the preceding claims, characterized in that further contact pads are provided on at least one of the conductor layers (14, 16) of the disentanglement board (10), in particular on the conductor layer which faces away from the metal core board. Circuit arrangement according to Claim 11 , characterized in that these further contact pads are arranged in such a way that further components, in particular SMD components, can be braided in. Circuit arrangement according to one of the preceding claims, characterized in that the unbundling board (10) is designed as an FR4 board. Circuit arrangement according to one of the preceding claims, characterized in that the at least one light source is an LED, in particular a high-performance LED. Circuit arrangement according to one of the preceding claims, characterized in that the disentanglement board (10) comprises a layer structure with at least three conductor layers, an insulator layer being arranged between each two conductor layers. Circuit arrangement according to Claim 15 with reference back to Claim 3 or a claim dependent thereon, characterized in that the wiring rows (Z1, Zn) and wiring columns (S1, Sn) are arranged on a conductor layer which is surrounded on both sides by an insulator layer. Circuit arrangement according to Claim 16 , characterized in that the surface of the disentanglement board (10) facing the metal core board has at least one groove (20) for discharging gas. Circuit arrangement according to one of the preceding claims, characterized in that the unbundling board (10) comprises a through hole (22) for discharging gases, the through hole (22) preferably passing through the contact pad (18) on the first conductor layer (14) of the unbundling board ( 10) is provided, which is coupled to at least one contact pad of the first conductor layer of the metal core board by a common soldering point. Method for producing a circuit arrangement for operating at least one light source with at least one metal core circuit board, which has a layer structure with at least one metal core, a first insulation layer, which is coupled to a first side of the metal core, and a first conductor layer, which is connected to the side facing away from the metal core the first insulation layer is coupled; a plurality of contact pads arranged on the first conductor layer; and at least one light source coupled to at least two of the plurality of contact pads; comprising the following steps: a) providing a disentanglement board (10), the disentanglement board (10) having an insulator core (12), a first conductor layer (14) coupled to a first side of the insulator core (12), and a second conductor layer ( 16) coupled to a second side of the insulator core (12), wherein a plurality of contact pads are provided on the first (14) and second conductor layers (16) of the disentanglement board (10); and b) coupling at least one contact pad (18) of the first conductor layer (14) of the disentanglement board (10) to at least one contact pad of the first conductor layer of the metal core board through a common soldering point.

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