Circuit board assembly

The invention relates to a circuit board assembly and a method of connecting at least two circuit boards 10, 20 together. A first circuit board 10 comprising a first slot 14 formed in said first circuit board 10 at its outer edge, which first circuit board 10 has a first set of conductive pads 16 formed adjacent to said first slot 14 and its extension 18 in said first circuit board 10 , is connected together with a second circuit board 20 comprising a second slot 24 formed in said second circuit board 20 at its outer edge, which second circuit board 20 has a second set of conductive pads 26 formed adjacent to said second slot 24 and its extension 28 in said second circuit board 20 . The first circuit board 10 is received in said second slot 24 formed in said second circuit board 20 and the second circuit board 20 is received in said first slot 14 formed in said first circuit board 10 .

DETAILED DESCRIPTION OF EMBODIMENTS On the drawings, FIG. 1 illustrates in schematic perspective view two circuit boards 10 , 20 , before assembly, according to the present invention. A first circuit board 10 comprises a first electronic circuit board pattern 12 formed on said first circuit board 10 , a first slot 14 formed in said first circuit board 10 at its outer edge, a first set of conductive pads 16 formed adjacent to said first slot 14 and its extension 18 in said first circuit board 10 , and a conductive lead 19 extending from each of the conductive pads 16 of the first set to said first electronic circuit pattern 12 . The circuit board assembly further comprises a second circuit board 20 comprising a second electronic circuit board pattern 22 formed on said second circuit board 20 , a second slot 24 formed in said second circuit board 20 at its outer edge, a second set of conductive pads 26 formed adjacent to said second slot 24 and its extension 28 in said second circuit board 20 , and a conductive lead 29 extending from each of the conductive pads 26 of the second set 26 to said second electronic circuit pattern 22 . As shown in FIG. 2 , the first circuit board 10 is received in said second slot 24 formed in said second circuit board 20 and the second circuit board 20 is received in said first slot 14 formed in said first circuit board 10 whereby each conductive pad 16 of the first set aligns with a corresponding conductive pad 26 of the second set. Each conductive pad 16 of the first set is electrically and mechanically connected with a corresponding conductive pad 26 of the second set to make an electrical and mechanical connection between the first and second circuit boards 10 , 20 . In this embodiment, the first and second electronic circuit board patterns 12 , 22 are arranged on both sides of said first and second circuit boards 10 , 20 , respectively. It is also possible to arrange the electronic circuit board patterns 12 , 22 on only one of the sides of said circuit boards 10 , 20 . In this embodiment, the first slot 14 and second slot 24 , respectively, reach from the outer edge of said first circuit board 10 to the centre of said first circuit board 10 and from the outer edge of said second circuit board 20 to the centre of said second circuit board 20 , respectively. It is also possible to arrange slots 14 , 24 that reach almost across the whole circuit board 10 , 20 or e.g. both slots reaching only a short distance from the outer edge into the circuit boards 10 , 20 as long as the first and second slots 14 , 24 interact with the first and second circuit board 10 , 20 in accordance with claim 1 of the present invention. In this embodiment, conductive pads 16 , 26 are arranged on both sides of both of said first and second circuit boards 10 , 20 whereby the conductive pads 16 , 26 advantageously transfer the stresses between the circuit boards 10 , 20 without weakening the coupling between the first and second circuit boards 10 , 20 as four contact “surfaces” are created between the first and second circuit boards 10 , 20 . The inherent strength associated with the circuit boards 10 , 20 is utilized to provide a stable mechanical contact and a stable electrical contact. In this embodiment, as can be seen in FIG. 1 , ten conductive pads 16 , 26 are arranged on each side of both of the circuit boards 10 , 20 thus summing up to twenty conductive pads 16 , 26 on each circuit board 10 , 20 , respectively, of which not all are shown in FIG. 1 . It is also possible to arrange more than ten or less than ten conductive pads 16 , 26 on each side of the circuit boards 10 , 20 . It is also possible to arrange the conductive pads 16 , 26 on fewer sides e.g. on both sides of at least one of said first and second circuit boards 10 , 20 or on one side of both of said first and second circuit boards 10 , 20 as long as the first and second conductive pads 16 , 26 interact according to claim 1 of the present invention. As illustrated in FIG. 3 the said first and second circuit boards 10 , 20 are preferably arranged at substantially right angles to each other. It is also possible to arrange the circuit boards at an angle of 45°-135° to each other whereby a decrease in building height of the circuit board assembly is achieved. Each conductive pad 16 of the first set is preferably electrically and mechanically connected by solder 30 with a corresponding conductive pad 26 of the second set to make an electrical and mechanical connection between the first and second circuit boards 10 , 20 . It is also possible to use other means of connection 30 , e.g. glue. As shown in FIG. 4 , it is also possible to connect at least one additional circuit board 40 to the first or second circuit board 10 , 20 whereby a more complex cross connection of several circuit boards is achieved.