Incandescent lamp and a lighting apparatus using the lamp

摘要

An incandescent lamp has an envelope having a bulbous portion including a wall defining a space, a thin tube extending outwardly along a central axis of the bulbous portion so as to communicate with the space, and a sealed portion located on an opposite end of the bulbous portion from the thin tube. The wall has a slope inclined toward the thin tube. A filament is provided along the central axis of the bulbous portion. An optical interference layer is arranged on a surface of the wall for reflecting infrared rays toward the filament. A first lead wire has a first end portion fixed in the sealed portion of the envelope, a second end portion coupled to one end of the filament and an intermediate U-shaped portion inserted into the thin tube for regulating a position of the filament. A second lead wire has a first end portion fixed in the sealed portion of the envelope and a second end portion coupled to another end of the filament.