Patent ID: 7604074

Claim:
A cutting element comprising: a substrate comprising a periphery and an interface surface; and an ultra hard material layer formed over the substrate and interfacing with said interface surface, wherein the interface surface comprises, a plurality of spaced apart projections formed inwardly and spaced apart from the periphery and arranged around an annular path, wherein each projection comprises a convex upper surface defining the projection, wherein each upper surface continuously and smoothly curves in the same direction increasing and then decreasing in height as viewed in cross-section along a plane through a diameter of the substrate, a first annular section extending to the periphery, a second section extending radially inward and above the first annular section, and a third annular section between the first annular section and the second section, wherein each of the plurality of spaced apart projections straddles the first annular section and the second section and extends across the first, second and third sections, wherein the second section extends to a height level, wherein each of said projections extends above said height level.