Patent ID: 8879274

Claim:
A method of manufacturing an electrical sensor with an exposed sensing surface, comprising the steps of: bonding an integral thin metal foil to an insulating substrate and thereby forming a component blank having an outer metal face of said metal foil; laser machining the outer metal face of the metal foil bonded to the insulating substrate of said component blank to produce at least one trench which defines one or more foil tracks cut through the metal foil of the component blank, said laser machining including the steps of a) preventing penetration of the insulating substrate, and b) forming said at least one trench to be at least equal in depth to the thickness of the thin metal foil to prevent current flow across the at least one trench between the one or more foil tracks; laser machining the insulating substrate of said component blank to produce one or more back slots in the insulating substrate connected to the at least one trench, whereby said one or more back slots and said at least one trench are together equal in depth to the full thickness of said component blank; and filling said at least one trench with a trench filling material; wherein said electrical sensor comprises said component blank, or is manufactured from said component blank, once said at least one trench has been filled with said trench filling material, and wherein said electrical sensor has an exposed sensing surface comprising said outer metal face of said metal foil.