| 摘要 |
PURPOSE:To prevent the extinguishing phenomena at the starting when combining a metal halide discharging lamp equipped with a tubular outer tube with a lead peak type ballast, by providing a specific relation between the diameter of a light emission tube and the diameter of the outer tube. CONSTITUTION:A silicon light emission tube 1 encapsulated with halogenation scandium and halogenation sodium together with the rare gas and mercury is contained in a tubular outer tube 7, while assuming the inner diameter of the light emission tube 1 is d(mm.) and the outer diameter of the outer tube 7 is D(mm.), the metal halide discharge lamp is formed to satisfy the relation 4.25<=D/d<=5.0. Consequently when combining it with a lead peak type ballast and lighting, the reignition voltage at the start can be lowered by suppressing the temperature rise of the light emission tube 1 within proper range thereby the extinguishing phenomena due to the rise of the reignition voltage can be prevented. |
