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AssigneeKoninklijke Philips Electronics N.V.
InventorsJunming Tu, Jay Joseph Palmer, Gregory Allen Golding
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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.
A ceramic metal halide lamp comprising a ceramic discharge tube (3) enclosing a gas-tight discharge space (11), a fill capable of sustaining an arc discharge in the discharge space (11), the fill comprised of a starting gas, mercury and a mixture of metal iodides, the metal iodides comprising sodium iodide, thallium iodide and at least a first rare earth halide component comprising at least one member selected from the group consisting of thulium iodide and gadolinium iodide, characterized in that the thulium iodide and/or gadolinium iodide is present in an amount within the range of about 55 to about 86 wt. % of the metal iodide mixture, whereby the light emission from the lamp has a high color temperature.
A ceramic metal halide lamp as claimed in claim 10, wherein a pair of discharge electrodes (4, 5) extend into the discharge space (11).
Dependencies are inferred from the claim text.