| 摘要 |
PURPOSE:To enhance heat radiating property, in a metal-base wiring board, on the surface of which a circuit is provided, by providing a hollow structure in the metal base. CONSTITUTION:In a metal-base wiring board, a circuit 2 is formed on metal plate 6 through an insulating layer 7. The metal plate 6 is made of aluminum, iron, copper, brass or the like and has hollow parts. The thicknesses of the metal plate 6, the insulating layer 7 and the circuit 2 are, 2-10mm, 40-150mum and 15-105mum, respectively. The size of the hollow part 8 and the pitch between partitioning walls 9 cannot be generally specified since they give effects on the mechanical strength of the metal plate 6. However, the size is usually about 1/4-3/4 the thickness of the metal plate, and the pitch is the same. Pipes are inserted into the hollow parts so as to provide a heat loop structure. Or a forced cooling means, which sends air with a blower, and the like is added. Thus the heat radiation property can be further enhanced. When electronic parts and heating elements are mounted on both surfaces, mounting density can be made high. |
