| 摘要 |
PURPOSE:To prevent a drop in an electromagnetic shielding effect by a method wherein, when individual wiring patterns related to a power supply and a signal cross a closed-circuit pattern for electromagnetic shielding use, they are formed at the inside of a board in a shape to be passed under the closed-circuit pattern in such a way that the crossed part is multilevel-crossed with the closed-circuit pattern. CONSTITUTION:When edge faces of shielding covers 3, 4 are formed so as to be close to individual corresponding closed-circuit patterns 2, individual wiring patterns 5, 6 related to a power supply and a signal are formed of the following: individual lands 5a, 6a formed respectively on the surface; individual through holes 5b, 6b formed at the inside of a board 1; and individual patterns 5c, 6c as their connecting conductors. The wiring patterns are formed in a shape to be passed under the closed-circuit patterns 2 in such a way that they are multilevel-crossed with the patterns. Consequently, it is not required to form an interrupted part at the closedcircuit patterns 2 and to form a hollow part in the shielding cover 3. As a result, the electromagnetic shielding effect of a printed wiring board is not obstructed. |
