Method of making module for automotive electrical systems
AssigneeI.S.T. Laboratories Ltd.
InventorMichael E. Dennis
Life of this patent
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Abstract
An electrical system for an automobile comprises a plurality of slave modules connected to one or more respective loads and/or sensors, a power bus connecting the slave modules to a power supply and a signal bus connecting the slave modules to a control module operable to remotely control the switching of power supplied to the loads by the slave modules and/or the sampling of signals from the sensors wherein at least one of the slave modules and/or the control means comprises a thick film printed circuit formed on a metal substrate. The system simplifies the wiring loom of a vehicle and provides circuits which are resistant to vibration and electrical interference.
Claims5
A method of forming a module of an electrical system for an automobile, comprising the steps of:
- subjecting to heat treatment a substrate formed from stainless steel sheet, the heat treatment being such as to heat the substrate to a temperature in the range 800 degrees C. to 1000 degrees C., whereby a chromium oxide layer is formed on the substrate;
- applying an initial adhesion layer of a dielectric material to a surface portion of the substrate such that an uncoated surface portion remains exposed, the dielectric material being selected to have a coefficient of thermal expansion substantially equal that of stainless steel;
- subsequently applying a final layer of a further dielectric material selected to have a coefficient of thermal expansion substantially matched to that of a thick film ink;
- applying electrical components including conductors by a screen printing process in which thick film inks are printed onto the final layer to thereby form a thick film circuit;
- and
- surface mounting further electrical components by soldering to conductors of the thick film circuit.
Dependencies are inferred from the claim text.