Tungsten-halogen light bulb and reflector lamp using the same

摘要

The present invention provides a tungsten-halogen light bulb having an arc tube (1) with a seal portion (5) at one end. A filament (8) is provided in the interior of the arc tube, and a basic gas mainly comprising at least either gaseous xenon or gaseous krypton is filled in the arc tube. When V (V) denotes a rated voltage of the tungsten-halogen light bulb, P(MPa) denotes a filling pressure of the basic gas at a room temperature, and Xe vol.% and Kr vol.% respectively denote composition ratios of the gaseous xenon and of the gaseous krypton, the following formulas (1) and (2) are satisfied simultaneously, in which '%' means 'volume %'. V≥100 (Volt) P≥0.7+ä0.1 x (Kr%/(Kr%+Xe%))ü In these formulas, Kr%+Xe%=100(%), 0≤Kr%≤100, and 0≤Xe%≤100. Accordingly, a crack at the seal portion (5) of the arc tube (1) is prevented and the lifetime is improved.