ELECTRICALLY CONDUCTIVE CONNECTION OF PRINTED CIRCUIT BOARDS

Description

[0001] The invention relates to an electrically conductive contact connection between a first and a second printed circuit board according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a method for producing an electrically conductive contact connection between a first circuit board and a second circuit board according to the preamble of claim 3.

[0003] Electrically conductive contact connections between components, for example printed circuit boards, are known from the prior art. From DE 41 32 995 A1, for example, it is known to solder contacts of a rigid printed circuit board to contacts of a flexible printed circuit board. Furthermore, it is known, for example, to connect two printed circuit boards, in particular a rigid and a flexible printed circuit board, to one another via so-called connector strips and printed circuit board sockets, pin or socket strips that are mounted on the printed circuit boards. Furthermore, from US 3,980,367 A, JP H08 213068 A and EP 2 107 642 A2, connections with the features of the preamble of claim 1 are known, in which a connecting element is first passed through openings in two or more printed circuit boards simultaneously and then a connection is established by deforming the connecting element.

[0004] EP 0 664 576 A2 discloses a connecting element which is first connected to a first circuit board by forming and then to another circuit board by pressing.

[0005] The object of the present invention is to provide an electrically conductive contact connection which is more cost-effective than the prior art and can be produced with less effort, and a method for producing the electrically conductive contact connection.

[0006] According to the invention, it is proposed that the first circuit board comprises a connection pin in the region of the contact connection and the second circuit board comprises a through-opening in the region of the contact connection, wherein the connection pin of the first circuit board is formed at least partially from an electrically conductive material and is pushed through the through-opening of the second circuit board, wherein the connection pin is deformed in a section projecting through the through-opening of the second circuit board beyond the second circuit board by a forming process, in particular a bending process or a riveting process, in such a way that a positive connection is formed between the first and the second circuit board.

[0007] The contact connection according to the invention can be manufactured without requiring any further soldering. Compared to a plug-in connection, the contact connection according to the invention requires little material expenditure.

[0008] The connection pin comprises in particular a cylindrical shape and is plastically deformable at least in a section protruding through the through-opening of the second circuit board, beyond the second circuit board.

[0009] The terminal pin is made, for example, of metal and / or an alloy and / or partly of plastic in combination with an electrically conductive material.

[0010] The connecting pin has been reshaped in the section protruding beyond the second circuit board through the through-hole of the second circuit board, under the action of force by means of a suitable tool, in such a way that the reshaped section holds the second circuit board partially projecting against the first circuit board.

[0011] Advantageously, an inner wall of the through-hole of the second circuit board comprises an electrically conductive material. The connecting pin of the first circuit board, which is inserted through the through-hole of the second circuit board, contacts the inner wall at least partially, preferably completely, thereby forming an electrically conductive connection.

[0012] The connection pin is connected to the first circuit board using a pin-in-paste soldering process. The connection pin is guided through an opening, a so-called component hole, in the first circuit board and soldered to the first circuit board. For example, the connection pin is soldered to the back of the first circuit board or, in the case of the pin-in-paste soldering process, to the opening in the first circuit board. With the pin-in-paste soldering process, solder paste is printed into the opening and the connection pin is then pushed through. When the solder paste melts, the liquid solder draws back into the opening and forms the soldered connection. It would also be conceivable for the connection pin to include a prefabricated setting head in a section projecting beyond the first circuit board on the back of the first circuit board, so that the rivet connection is closed by reshaping the section projecting beyond the second circuit board.

[0013] Alternatively, the pin is connected to the first circuit board using a surface-mounting technology (SMT) soldering process. The pin is then soldered directly to the first circuit board using solderable pads.

[0014] The first circuit board is a rigid circuit board, and the second circuit board is a flexible circuit board. The first circuit board comprises, for example, a non-conductive carrier material, a glass fiber mat impregnated with epoxy resin, also known by the material identifier FR4. The second circuit board is, for example, a particularly thin circuit board based on polyimide films. Such circuit boards can be advantageously used in a space-saving manner, particularly by folding them into very tight structures, for example in lighting devices, and / or for connecting two rigid circuit boards, for example in lighting devices.

[0015] Further preferred embodiments relate to a method for producing an electrically conductive contact connection between a first printed circuit board and a second printed circuit board, wherein the first printed circuit board comprises a terminal pin in the region of the contact connection and the second printed circuit board comprises a through-hole in the region of the contact connection, wherein the terminal pin of the first printed circuit board is formed at least partially from an electrically conductive material, characterized in that the terminal pin of the first printed circuit board is pushed through the through-hole of the second printed circuit board, and then a section of the terminal pin projecting through the through-hole of the second printed circuit board over the second printed circuit board is formed in a forming process, in particular a bending process or a riveting process, in such a way thatthat a positive connection is formed between the first and the second circuit board.,

[0016] In the forming process, the connecting pin is formed in the section protruding through the through-hole of the second circuit board, beyond the second circuit board, under the action of force by means of a suitable tool, in such a way that the formed section subsequently holds the second circuit board partially projecting against the first circuit board.

[0017] The forming comprises, for example, a so-called upsetting of the connecting pin and / or the pre-forming of a rivet head, in particular by circular blows with the ball-head hammer, and / or the final forming of the rivet head, in particular by means of a rivet head setter.

[0018] In a previous step, the connection pin is connected to the first circuit board using a pin-in-paste soldering process.

[0019] Alternatively, the terminal pin is connected to the first circuit board in a preceding step using a surface mounting technology (SMT) soldering process. Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Like reference numerals in different figures designate like or at least functionally comparable elements. They show, in schematic form: Fig. 1 shows an electrically conductive contact connection according to the invention in accordance with a first preferred embodiment; Fig. 2 shows an electrically conductive contact connection according to the invention in accordance with a further preferred embodiment; and Fig. 3 shows circuit boards connected to one another using contact connections according to the invention.

[0020] Fig. 1shows an electrically conductive contact connection according to the invention according to a first preferred embodiment in a sectional view, which is designated in its entirety by the reference numeral 10. The contact connection 10 connects a first circuit board 12 to a second circuit board 14. The second circuit board 14 comprises a through-hole 16, and the first circuit board 12 comprises a terminal pin 18, which is inserted through the through-hole 16 of the second circuit board 14.

[0021] The terminal pin 18 is formed at least partially from an electrically conductive material. According to the Figure 1 In the illustrated embodiment, the terminal pin 18 is mounted on a surface 20 of the first circuit board 12. According to the invention, the terminal pin 18 is connected to the surface 20 of the first circuit board 12 by means of an SMT (surface mounting technology) soldering process.

[0022] An inner wall 22 of the through-hole 16 of the second circuit board 14 comprises an electrically conductive material. The connecting pin 18 contacts the inner wall 22 at least partially, preferably over its entire circumference, thereby forming an electrically conductive connection between the first circuit board 12 and the second circuit board 14.

[0023] The connecting pin 18 is formed in a section 24 projecting through the through-hole 16 of the second circuit board 14 beyond the second circuit board 14 by a forming process, in particular a bending process or a riveting process, such that a positive connection is formed between the first and second circuit boards 12, 14. The formed section 24 partially protrudes the second circuit board 14 against the first circuit board 12.

[0024] The forming process is carried out by applying force using a suitable tool. The forming process includes, for example, a so-called upsetting of the connecting pin 18 and / or the pre-forming of the section 24 into the shape of a rivet head, in particular by circular impacts with a ball-head hammer, and / or the final forming of the section 24 into the shape of a rivet head, in particular using a rivet head setter.

[0025] Figure 2 shows the contact connection 10 according to another embodiment in a sectional view. The connection pin 18 of the first circuit board is connected to the first circuit board 12 by means of a through-hole plating.

[0026] For this purpose, the first circuit board 12 comprises an opening 26, a so-called component hole. The connection pin 18 is passed through the opening 26 of the first circuit board 12 and soldered to the first circuit board 12. According to the invention, the connection pin 18 is soldered to the first circuit board 12 in the opening 26 using a pin-in-paste soldering process. For this purpose, a solder paste is first printed into the opening 26 and then the connection pin 18 is pushed through. When the solder paste melts, the liquid solder withdraws into the opening 26 and forms the solder connection 28. According to an embodiment not shown, it is also conceivable for the connection pin 18 to be soldered to a rear side 30 of the first circuit board 12.

[0027] It would also be conceivable for the connecting pin to comprise a prefabricated setting head in a section projecting beyond the first circuit board 12 on the rear side 30, so that the rivet connection is closed by reshaping the section 24 projecting beyond the second circuit board 14.

[0028] Figure 3shows a side view of several printed circuit boards 12, 14 connected to one another by contact connections 10 according to the invention. The first printed circuit board 12 is a rigid printed circuit board, and the second printed circuit board 14 is a flexible printed circuit board. Furthermore, a further rigid printed circuit board 12' is provided. The first printed circuit board 12 comprises, for example, a glass fiber mat impregnated with epoxy resin, which is also known by the material identifier FR4, as a non-conductive carrier material. The second printed circuit board 14 is, for example, a particularly thin printed circuit board based on polyimide films. According to the illustrated embodiment, the second printed circuit board 14 is provided for connecting the two rigid printed circuit boards 12, 12'. Such a use is conceivable, for example, in lighting devices, in particular for connecting LED printed circuit boards.An LED circuit board comprises one or more LEDs, with multiple circuit boards being used in particular in lighting devices with multi-chamber reflectors and / or with multiple feed points.

Claims

1. Electrically conductive contact connection (10) between a first and a second circuit board (12, 14), comprising the first and the second circuit board and a connection pin (18), the first circuit board (12) being a rigid circuit board and the second circuit board (14) being a flexible circuit board, the first circuit board (12) comprising the connection pin (18) in the region of the contact connection (10) and the second circuit board (14) comprising an insertion opening (16) in the region of the contact connection (10), the connection pin (18) of the first circuit board (12) being at least partially formed from an electrically conductive material and being inserted through the insertion opening (16) of the second circuit board (14), the connection pin (18) being formed in a portion (24) protruding through the insertion opening (16) of the second circuit board (14) beyond the second circuit board (14) by a forming process, in particular a bending process or a riveting process, in such a way that that a form-fitting connection is formed between the first and the second circuit board (12, 14), characterized in that the connection pin (18) is connected to the first circuit board (12) by means of a pin-in-paste soldering process or by means of an SMT (surface mounting technology) soldering process.

2. Contact connection (10) according to claim 1, characterized in that an inner wall (22) of the insertion opening (16) of the second circuit board (14) comprises an electrically conductive material.

3. Method for producing an electrically conductive contact connection (10) between a first circuit board (12) and a second circuit board (14), comprising the first and the second circuit board (12, 14) and a connection pin (18), the first circuit board (12) being a rigid circuit board and the second circuit board (14) being a flexible circuit board, the first circuit board (12) comprising the connection pin (18) in the region of the contact connection (10) and the second circuit board (14) comprising an insertion opening (16) in the region of the contact connection (10), the connection pin (18) of the first circuit board (12) being at least partially formed from an electrically conductive material, the connection pin (18) of the first circuit board (12) being inserted through the insertion opening (16) of the second circuit board (14), and then a portion (24) of the connection pin (18) protruding through the insertion opening (16) of the second circuit board (14) beyond the second circuit board (14) being formed in a forming process, in particular a bending process or a riveting process, in such a way that a form-fitting connection is formed between the first and the second circuit board (12, 14), characterized in that the connection pin (18) is connected to the first circuit board (12) in a preceding step by means of a pin-in-paste soldering process, or in that the connection pin (18) is connected to the first circuit board (12) in a preceding step by means of an SMT (surface mounting technology) soldering process.