| 摘要 |
PURPOSE: To eliminate the additional application of sheet to a printed board device, which is provided by mounting electronic components on a printed board. CONSTITUTION: A printed board 16 is provided with a through hole 15, the diameter of the through hole 15 on the printed board rear side 19 is smaller than that on the printed board front side 18. During the reflow process, since the the hole diameter on the printed board front side is large, metal particles of cream solder 17 are prevented from being sucked up to the printed board front side 18 on the printed board top face, even with the capillary phenomenon of the cream solder 17, because the a space between the hole 15 of the printed board 16 and a lead terminal 6 is small.
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