Low-pressure mercury vapour discharge lamp
AssigneeU.S. Philips Corporation
InventorsJohannes T. C. van Kemenade, Gerardus H. M. Siebers, Jean J. Heuvelmans, Johannes T. W. deHair, Johannes W. ter Vrugt
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Abstract
A low-pressure mercury vapor discharge lamp with a luminescent layer whose emission mainly lies in three spectral ranges and whose loading amounts to at least 500 W per m.sup.2 surface area of the luminescent layer, is characterized by having an absorption layer of a luminescent aluminate activated by trivalent cerium and having a garnet crystal structure. The absorption layer permits the obtaining of low color temperatures (down to 2000 K.).
Claims18
A low-pressure mercury vapour discharge lamp, whose emission mainly lies in three spectral ranges and whose colour temperature of emission lies in the range of 2000-3000 K., the lamp comprising a gas-tight discharge envelope transparent to radiation and having a gas filling comprising mercury and a rare gas, a luminescent layer comprising luminescent materials whose emission mainly lies in the ranges of 590-630 nm and 520-565 nm, means for maintaining a column discharge in the gas filling, the power consumed by the column being at least 500 W per m.sup.2 surface area of the luminescent layer,
- characterized in that the lamp is provided with an absorption layer comprising a luminescent aluminate activated by trivalent cerium and having a garnet crystal structure.
Dependencies are inferred from the claim text.