| 摘要 |
PROBLEM TO BE SOLVED: To keep a thermal land comparatively small in size and further suppress radiation of heat. SOLUTION: In a thermal land 13, heat transmitted from a part fitting hole 12 filled with solder is transmitted to a circular copper foil area 17 around the edge of the part fitting hole 12, and then it is collected into a nearest inner spoke area 27 among four inner spoke areas 27 from the circular copper foil area 17. The heat is conducted to an outer spoke area 28 from the respective inner spoke areas 27 along the circumferential direction of a narrow-width copper area 26, and it is transmitted to a flat pattern area around the thermal land from the outer spoke area 28. Therefore, a thermal conduction route is added along the circumferential direction, and an effect of increasing heat capacity can be attained as a whole. Thus, the radiation of heat can be further suppressed, while temperature inside a through-hole can be efficiently increased. COPYRIGHT: (C)2007,JPO&INPIT
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