Armstrong, Westerman, Hattori, McLeland & Naughton
Grounding structure of a printed wiring board
 At least one grounding through hole filled with solder is provided in a printed wiring board near by a fixing hole through which a screw fixes the board to a frame, penetrating a ground layer provided on an upper surface of the board and a substrate, made of insulating material, of the board. A metal layer made of electrically conductive and solderable material is plated on an inner surface of the grounding through hole so that melted solder is raised to an upper surface of the board. An upper end of the metal layer is formed to a flange electrically connected with the ground pattern so that the melted solder is raised from the upper surface of the board, forming a spherical end of the solder. 
Fujitsu Isotec Limited
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Shinya
Watanabe