| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed board having superior electromagnetic wave noise shielding characteristic. SOLUTION: The ultra thin high-silicon steel plate, whose Si content is >=5% and <=7%, and whose thickness is <=0.3 mm, is used in this printed board. At least one or more ultra-thin high-silicon steel plates are used in this printed board, the high-silicon steel plate has a Si-concentration gradient in the plate- thickness direction, the Si-concentration at the surface layer is higher than that at the central part of the steel-plate, the difference between the Si contents at the surface layer and at the central part of the steel-plate is >=0.5%, the average Si content in the plate-thickness direction is >=3% and <=7%, and the plate thickness is <=0.3 mm. |
