Koito Manufacturing Company, Ltd.

Tokyo Electric Co.

Hiromi Kubota

Shinya Misonou

Masayasu Hirata

Toshiyuki Kambe

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.

Method and apparatus for welding shroud glass tube in arc tube for discharge lamp

A timer device includes a housing for containing a timer circuit and a time unit setting switch to select one of plural time units in the timer circuit. At least two scale plates each have a through-hole for the insertion of a timer circuit knob, engaging projections provided on the edge of each plate, and an engagement releasing recess provided at an edge of each plate. Engaging recesses provided on the housing are engageable with the projections when a selected plate is attached to the housing, and an escaping recess provided on the housing and overlapping the releasing recess, when the plate is attached to the housing, enables access to be attained from outside to the underside of the plate through the recesses. A depression is formed on the plate into which a button of the time unit setting switch is insertable when the button is located at that position which sets in the timer circuit a time unit corresponding to the scale on the plate, and the plate is thus enabled to be attached to the housing. The switch then is also prevented from moving from its initial position. The switch button is blocked from insertion into the depression, so as to prevent the plate from being attached to the housing, when the time unit represented by the scale on the plate does not coincide with the time unit set by the switch in the timer circuit.

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Shizuoka, Japan

Hiromi Kubota