Abstract: A high-power ceramic discharge metal halide (CDM) lamp with a shroud-type containment assembly is disclosed. The lamp includes: a first shroud (138) with a first wall which forms a cylinder and which defines a first cavity; a second shroud (136) situated within the first cavity and which includes a second wall which forms a cylinder and which defines a second cavity situated within the first cavity of the first shroud; a first coil portion (140, 142) is situated about at least the one or the first and second shrouds (respectively); a ceramic arc tube (102) is situated in the second cavity and includes first and second openings, first and second leads (104, 106) with electrodes, and a lamp cavity (103) for containing a fill.

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.