| 摘要 |
PURPOSE:To effectively use the power of plasma that is emitted from an opening to an outer tube and improve the efficiency of a lamp by providing a layer that applying a different phosphor from that of an inner tube to the outer tube. CONSTITUTION:The inner surface of inner tubes 2 and 3 is coated with a rare earth phosphor of 5mg/cm<2> in thickness. The inner surface of an outer tube 1 is coated with a halogenated phosphor for general illumination of 3mg/cm<2> in thickness. Since the temperature of the outer tube is lower than that of the inner tube and the density of plasma emitted from an opening is lower than that of the inner part of the inner tube, this purpose can fully be attained using an economical halogenated phosphor that is used normally without coating the inner surface of the outer tube with an expensive phosphor. |
