Koito Manufacturing Company, Ltd.

Masayasu Hirata

Shinya Misonou

Hiromi Kubota

A method of secondarily welding one end of a shroud glass tube covering an arc tube body having a discharge emitting portion, having the other end welded primarily to one of the arc tube body ends, to the other end side of the arc tube body, while discharging air from, and introducing an inactive gas into, the tube through the opening end of the glass tube to hold a negative pressure. Heating and melting from a side is carried out. The opening end of the glass tube is connected to a piping passage component for discharging air and introducing an inactive gas through a rotatable magnetic fluid seal unit. Secondary welding is carried out with the rotation of the glass tube around an axis. The glass tube rotated with respect to secondary side heater is uniformly heated, molten and softened circumferentially, and welded along the arc tube body outer periphery.

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Shizuoka, Japan

Masayasu Hirata