Abstract: A ceramic metal halide lamp (1) of the present invention has a ceramic discharge tube (3) and two electrodes (4, 5) mounted in an outer glass envelope (2). The discharge tube (3) is filled with mercury, a starting gas such as xenon and a mixture of metal iodides including in weight percent (wt. %): about 5-35% sodium iodide, about 1-6% thallium iodide, about 55-86% thulium iodide and/or dysprosium iodide, about 0-15% calcium iodide and about 0-31% of dysprosium and/or holmium iodide. The lamp has a light output characterized by a relatively high color temperature (around 5000K or higher), making it suitable for use as a daylight lamp.

Abstract: The hot re-strike time of a high wattage (150 W or greater) ceramic discharge metal halide (CDM) lamp is reduced by: (a) increasing the ratio A of the diameter (D2) of the outer bulb (1) to the inner diameter (ID) of the discharge vessel (3); or (b) filling the outer bulb with an inactive gas such as nitrogen, helium, neon, argon, krypton or xenon; or by implementing both (a) and (b). The hot re-strike time can be further reduced by combining (a) and/or (b) with (c), the addition of a getter metal for iodine, such as Sc, Ce or Na, to the discharge vessel (3).