Printed circuit device

Claim 1

A printed circuit device comprising: a ceramic base plate; and a circuit pattern layer disposed on one surface of said base plate, said circuit pattern layer comprising a plurality of electric conductor layers and insulating layers in an alternate stacked laminar-arrangement, said electric conductor layers and said insulating layers each having a predetermined pattern, a predtermined part of said circuit pattern being constituted by a first conductor layer, an intermediate conductor layer, a second conductor layer, a first insulating layer, and a second insulating layer, said intermediate conductor layer being stacked adjacent said first insulating layer on one surface thereof and being stacked adjacent said second insulating layer on the other surface thereof, said first insulating layer being stacked with said first conductor layer, said second insulating layer being stacked with said second conductor layer, said first and second insulating layers being connected and forming an insulating enclosure which is disposed around intermediate conductor layer in a cross section taken along a plane perpendicular to the surface of the base plate, said first and second conductor layers being connected and forming a conductor enclosure disposed around said insulating enclosure in said cross section, said intermediate conductor layer forming a conducting layer electrically connected to a power supply terminal mounted on said base plate, said conductor enclosure forming an electric conductive layer for grounding, said intermediate conductor layer being apropriately formed with narrow parts and wider parts in its extension, coil parts being formed by said narrow parts, and capacitor parts being formed by said narrow parts, said wider parts, said insulating enclosure, and said conductor enclosure, said coil parts cooperating with said capacitor parts so as to constitute the equivalent of a low-pass filter on only one surface of said base plate.