PURPOSE: To improve the adhesive strength between a lead wire and a metal base, eliminate the non-lighting of this double metal base type lamp and the generation of its flickering, provide the lamp with a long life, and simplify welding work by inserting soft conductive material between the cone tip section of the base and the lead wire, crushing the cone tip section, and crimping the lead wire through the soft conductive material.

CONSTITUTION: The cont tip section of a conical trapezoidal metal base is crimped and a lead wire 5 is inserted in this crimping section 10 through soft conductive material 11. The soft conductive material 11 consists of gold, silver, tin, platinum, copper, lead, or these alloys, for example, such as solder, or conductive rubber. The material is preformed in a tube form and is inserted in the cone tip section of a metal base 3. Following the crushing of this cone tip section, the material is crushed simultaneously and crimps the lead wire 5.