Patent ID: 6576492
Filing Date: 2003-06-10
Classification: H01C

Abstract:
A process for making surface mountable electrical devices, comprising the steps of:preparing at least first and second PTC sheets which have a positive thermal coefficient characteristic and each of which has opposite first and second contact faces; respectively covering said first and second contact faces of each of said first and second PTC sheets with outer and inner metal foil sheets; selectively masking said inner metal foil sheet on each of said first and second PTC sheets to define a pattern of exposed areas on said inner metal foil sheet; removing portions of said inner metal foil sheet on each of said first and second PTC sheets at said exposed areas so as to define a pattern of non-inlaid portions of said second contact face of each of said first and second PTC sheets, said non-inlaid portions being exposed from said inner metal foil sheets; laminating said first and second PTC sheets and said outer and inner metal foil sheets to form a laminate such that said non-inlaid portions of said second contact face of said first PTC sheet are respectively bonded to said non-inlaid portions of said second contact face of said second PTC sheet and that said inner metal foil sheet on said first PTC sheet overlaps said inner metal foil sheet on said second PTC sheet; selectively masking said outer metal foil sheet on said first contact face of said first PTC sheet to define a pattern of exposed areas on said outer metal foil sheet on said first PTC sheet; removing portions of said outer metal foil sheet on said first PTC sheet at said exposed areas so as to define a pattern of first slits in said outer metal foil sheet on said first PTC sheet; forming a plurality of first bores in said laminate along intersecting cutting lines at locations where said cutting lines intersect, each of said first bores extending from said outer metal foil sheet on said first PTC sheet to said outer metal foil sheet on said second PTC sheet in a transverse direction relative to said first and second contact faces; forming a conductive first transverse layer in an interior of each of said first bores such that said first transverse layer extends from said outer metal foil sheet on said first PTC sheet to said outer metal foil sheet on said second PTC sheet; and cutting said laminate along said cutting lines to form a plurality of said surface mountable electrical devices such that said outer metal foil sheet on said first PTC sheet on each of said surface mountable electrical devices forms opposing first and second segments which are spaced apart by a respective one of said first slits and that said first transverse layer on each of said surface mountable electrical devices is electrically connected to said first segment of said outer metal foil sheet on said first PTC sheet, said inner metal foil sheets, and said outer metal foil sheet on said second PTC sheet.