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AssigneePatent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
InventorAndreas Genz
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A high-pressure metal-halide discharge lamp (1) having a mean arc power been 60 and 140 W/mm arc length includes a discharge vessel (2), two electrodes (5,6), a fill of mercury, at least one noble gas, at least one halogen, cesium, and tantalum and dysprosium for forming metal halides to produce light with a color temperature between 400 and 700 K at a wall load of between 40 and 85 W/cm.sup.2 wall area. The tantalum maintains the halogen cycle process at relatively low wall loads, and thus prevents blackening and devitrification of the bulb, while dysprosium provides a high radiation flux in the visible range of the optical spectrum and thus optimizes color reproduction. At a wall load of between 40 and 85 W/cm.sup.2, optimum results are attained if the fill contains from 0.2 to 1.5 mg of tantalum and dysprosium per cm.sup.3 of vessel volume, in a weight ratio of tantalum to dysprosium of between 0.3 and 1.5. As a result, lamp service life of 1500 hours at a color temperature of 5500 K are attained.
A high-pressure metal-halide discharge lamp (1), having a mean arc power between 60 and 140 W/mm arc length for fitting in optical systems, having a discharge vessel (2) of high-temperature-proof transparent material, two high-temperature-proof electrodes (5, 6), and a filling that comprises mercury, at least one noble gas, at least one halogen, cesium, and further metals for forming metal halides, characterized in that to produce light with a color temperature between 4000 and 7000 K, at a wall load at the lamp (1) between 40 and 85 W/cm.sup.2 at wall area, the filling contains tantalum and dysprosium as further metals.
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