Electrically connecting together 2-printed type circuit boards - by e.g. applying circuit of conducting thermoplastics to two insulating sheets, ultrasonically bonding them together under pressure and cooling

摘要

Top and bottom printed type circuit boards are connected together electrically as follows: a heat-softened material is mixed with conducting material and the prod. is applied to an upper insulating sheet to form the first circuit; the mix is similarly applied to a second insulating sheet; the top sheet is placed on the second sheet so that their circuits meet; the top and bottom circuits and the top sheet are subjected to ultrasonic vibrations so as to heat frictionally and melt them all, while the top sheet is pressed down on to the lower sheet to bond them together; finally the top and bottom circuits are cooled to produce a durable connection. The circuits are preferably, e.g., polyester or polyimide PCB's; the process preferably uses a dispersion of thermoplastic polyester, PVC, polyvinylacetate, ethylene-vinylacetate copolymer, polyurethane, polystyrene or phenoxy polymer in a plasticiser or solvent from the group of isophorone, carbinol, cyclohexane or dibutylphthalate; pigments can also be added, as well as one or more types of rubber from the range of chloroprene, acrylonitrile, styrene-butadiene or natural rubber. ADVANTAGE - The procedure is cheap and rapid. The prods. can be thin for miniaturised electronic equipment or components. The sheets can be bonded in any disposition.