Filament lamp and light irradiation heat treatment device
A filament lamp has a bulb comprised of a straight light emitting tube from which a pair of flat hermetically sealed portions extend, a plurality of coiled filaments arranged within the light emitting tube, in the tube axis direction a pair of internal leads are connected to ends of the filament by a respective one of a plurality of metal foils that are embedded in the hermetically sealed portions, and external leads are connected to the metal foils. The width of metal foils embedded in the hermetically sealed portions is increased so as not to cause them to melt even when an electric current to be supplied to the filament lamp is increased, the hermetically sealed portions being made wider than the external diameter of the light emitting tube and the width between outer margins of the metal foils in a direction at right angles of the tube axis is greater than the internal diameter of the light emitting tube.
1. A filament lamp, comprising:
a bulb comprised of a straight light emitting tube and a pair of flat hermetically sealed portions continuously formed at each of opposite ends of the light emitting tube,
a plurality of coiled filaments sequentially aligned and arranged in a tube axis direction within the light emitting tube,
a pair of internal leads, each of which is connected to a respective one of the ends of the filament,
a plurality of metal foils spaced from each other, embedded in the hermetically sealed portions, and connected to the internal leads, and
external leads connected to the metal foils,
wherein the hermetically sealed portions are wider than the external diameter of the light emitting tube; and
wherein the width, in a direction at right angles of the tube axis and defined between two parallel lines extending in the tube axis direction, between outer margins of two of the metal foils arranged at opposite ends of each hermetically sealed portion in the direction at right angles of the tube axis is greater than the internal diameter of the light emitting tube.
2. Light irradiation type heat treatment device having a lamp unit with a plurality of filament lamps, each of the filament lamps comprising:
a bulb comprised of a straight light emitting tube and a pair of flat hermetically sealed portions, each of which is continuously formed at a respective one of opposite ends of the light emitting tube and having a width that is greater than the external diameter of the light emitting tube,
a plurality of coiled filaments sequentially aligned and arranged in a tube axis direction within the light emitting tube,
a pair of internal leads, each of which is connected to a respective one of the ends of the filament,
a plurality of metal foils spaced from each other, embedded in the hermetically sealed portions, and connected to the internal leads, and
external leads connected to the metal foils,
wherein the width, in a direction at right angles of the tube axis and defined between two parallel lines extending in the tube axis direction, between outer margins of two of the metal foils arranged at opposite ends of each hermetically sealed portion in the direction at right angles of the tube axis is greater than the internal diameter of the light emitting tube, and
wherein the flat hermetically sealed portions are arranged extending in parallel in the vertical direction to an article to be treated.