FLEXIBLE-RIGID MULTILAYERED BOARD AND ITS MANUFACTURE

摘要

PURPOSE:To prevent the occurrence of characteristic impedance mismatching between hard board sections and a flexible section so that signals can be transmitted without loss by making the thickness of a signal circuit thinner in the flexible section than that in the hard board sections. CONSTITUTION:Two rigid board sections 1 which are rigid multilayered printed wiring boards are united in one body by using the flexible section 2 of a flexible printed wiring board. Both sections 1 and 2 are provided with sealed layers 3 as their outermost layers (both surfaces) and the layers 3 are isolated from an internal signal circuit 4 by interposing insulating layers between them. In addition, the sealed layers 3 of both sections 1 and 2 are connected to each other through a through hole 6. The signal circuit 4 is continuously formed from one hard board section 1 to the other hard board section 1 through the flexible section 2 and the width of the circuit 4 is not changed in the sections 1 and 2, but the thickness of the circuit 3 is made thinner in the flexible section 2 than that in the hard board sections 1. The insulating layers 5 between the layers 5 and circuit 5 are formed thicker in the hard board sections 1 and thinner in the flexible section 1.