Abstract: A circuit board is manufactured by applying a film of heat actuable adhesive to a substrate and depositing on the film a layer of a conductive powder. The powder and film are then activated by laser radiation or by direct contact with a heated plate. The excess powder is then removed and the substrate fired to cure or bond the powder to the substrate while removing excess adhesive film.

Abstract: A process for the manufacture of circuitry in the form generally known as circuit boards comprises the manufacture of a master pattern from a conductive layer and a superposed non-conductive layer which can receive an electrical charge. The master pattern is contacted by a developer containing a conductive material in the form of powder or ink which transfers the conductive material to the pattern layers on the master pattern by electrostatic force. A non-conductive substrate is then brought to a position closely adjacent to the master pattern and electrostatic forces used to transfer the particles from the master pattern onto the substrate in the required pattern. The particles are then fixed by heating. Multiple layer circuits can be built up using nonconductive layers. A coating can be applied to the conductive particles to enable them to accept an electrostatic charge, the coating being dissipated during the heat fixing.