| 摘要 |
PURPOSE: To obtain a metal core board whose radiation is increased even from the rear of a metallic substrate by a method wherein the rear of the metal core board in which a circuit pattern part used to mount a circuit element has been formed on the surface of the metallic substrate is black. CONSTITUTION: A black anodic oxide coating layer 5 is formed on the whole rear of a metallic substrate 1. Assuming that the surface area S of the metallic substrate is 0.00696m<2> , its total loss quantity of heat Q is 7W and an ambient temperature Ta is 25 deg.C, the surface emissivityε=0.8 of a black anodic oxide coating treatment is substituted in Expression so as to be computed (in Expression, a surface temperature T=Ta+ΔT, and A is 5.2 in terms of the experimental value of an enclosure). Then, in the case of the black anodic oxide coating treatment, a theoretical temperature rise T is suppressed to 29.3 deg.C. Actually, when the rear of the metallic substrate 1 is formed to black in such a way that the surface radiation is 0.7 to 0.9 at room temperature, the radiation from the rear of the metallic substrate can bee increased.
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