US Patent 7167071 Inductive device and method for producing the same

A core material-including organic core board or inorganic sintered board 1 having a plurality of band-shaped conductor patterns 2 formed on its front and rear surfaces is sliced in a direction crossing the band-shaped conductor patterns 2. End portions of the band-shaped conductor patterns 2 exposed on each of cut surfaces of the core board 1 are connected to one another by bridging conductor patterns formed on the cut surfaces. In this manner, at least one helical coil is provided. The inner diameter of the helical coil can be kept constant while coil pitch accuracy can be kept good.