Sandwiched insulative/conductive layer emi shield structure for printed

Abstract

Using a thermal/vacuum forming process a thin film polymer substrate is shaped into a generally shroud-like EMI shield body which forms a portion of a multi-layer EMI shield structure removably secured to a side of a printed circuit board disposed within a plastic computer housing, over operating components disposed on the circuit board. An inner side of the polymer substrate body, which faces the operating components, has a metallic conductive layer formed thereon which, in turn, is covered by a layer of insulative material. During the application of the insulative material to the conductive layer, spaced, coplanar attachment portions of the metal clad shield body are masked on their inner sides so that in the finished EMI shield structure the conductive material on these attachment portions is exposed. When the attachment portions of the EMI shield structure are screwed to the component side of the circuit board with metal fasteners the conductive layer of the shield is conductively communicated with the internal ground plane of the printed circuit board via the metal fasteners. By connecting the EMI shield structure to the circuit board in this manner, the necessity of forming a metallic coating on the plastic computer housing, to create the requisite EMI shielding on the computer, is advantageously eliminated.