摘要 |
A bulb comprises an airtight envelope having a filling gas therein. A conductive wire extends outwardly from the airtight envelope. A conductive pipe pin has the conductive wire passed therethrough, a predetermined welding portion, and a welded portion including a smooth surface. An outer diameter of the welded portion is no greater than the outer diameter of the pin. The welded portion may be formed in the pipe pin by the fluid of the melted conductive wire and predetermined welding portion flowing into the pipe pin and hardening.
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