| 摘要 |
PURPOSE: To obtain a printed-wiring board which prevents electromagnetic waves discharged from a first wiring pattern from being leaked to the outside of a closed space by a method wherein the first wiring pattern to be shielded is inside an electromagnetic closed space constituted of a second wiring pattern for electromagnetic wave cutoff, a third wiring pattern, and an interlayer connecting line. CONSTITUTION: A wiring pattern 11 for a power supply is formed on a wiring layer V, and a wiring pattern 12 for grounding is formed on a wiring layer E. Ends, on one side, of via holes 14 are connected to the grounding pattern 12, they are passed through respective wiring layers S2Y, S2X and V, and ends on the other side are connected to a grounding pattern 13 on a wiring layer S1Y. The grounding pattern 12 and the power-supply pattern 11 are connected by a bypass capacitor for decoupling. Thereby, a space which is electromagnetically closed by the power supply pattern 11, the grounding pattern 12 and the via holes 14 in a plurality, and it is possible to prevent electromagnetic waves discharged by making use of the wiring layers S2X, S2Y as antennas from being leaked to the outside of the space. |
