| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a printed wiring board which eliminates poor heating of component soldering lands and cream solder for the reflow soldering of large-heat capacity components. SOLUTION: Vias 7a, 7b, connected to outer layer positions 6a, 6b formed on inner layer patterns 5a, 5b, 5c or surface 1b of a 4-layer printed wiring board 1, are connected directly to component soldering lands 3a, 3b. Heat 8b given to other surface 1b of the wiring board 1 is conducted to the patterns 6a, 6b and is gathered to lands 2a, 3b through the vias 7a, 7b, as well as heats the entire wiring board 1, thus the heat conducted to the patterns 5a-5c to the lands 3a, 3b through the vias 7a, 7b is collected.</p> |
