| 摘要 |
PURPOSE:To improve the reliability of a metal vapor discharge lamp, by eradicating a trouble such as the breaking of filament, the initial miss of lighting or the like by using a fixed resistance element having a definite allowable temperature instead of a filament for heating a bimetal. CONSTITUTION:At least a heat responce element 4 to start a luminous tube 1, a bimetal or the like and a fixed resistance element 26, which allows the temperature of 200 deg.C and above, to operate a bimetal 4 or limit the current flowing the element 4 are arranged in an outer tube 7 instead of a filament, and rare gas as xenon or the like, which diminishes a surge voltage generated when the bimetal 4 operates, is enclosed in the outer tube. As the fixed resistance element 26, a carbon resistance, an iron oxide resistance, a zinc oxide resistance, a PTC thermistor or the like may be used. Thereby, as it does not function as an electrode when a discharge occurs in the outer tube 7, the miss of lighting at an early stage is prevented, and the reliability is improved. |
