Abstract: Low-pressure mercury vapor discharge lamp in which the envelope (1) is provided on its inside with a luminescent layer (5), which comprises green luminescing Zn.sub.2 SiO.sub.4 :Mn.sup.2+ (willemite), while between the luminescent layer (5) and the envelope (1) a luminescent intermediate layer (6) is present, which comprises luminescent Sr.sub.4 Al.sub.14 O.sub.24 : Eu.sup.2+, in which the Sr may be replaced for up to 25 mol. % by Ca.

Abstract: Low-pressure mercury vapor discharge lamp having a very satisfactory color rendition and a color temperature from 2300 to 3300 K. The lamp is provided with a luminescent layer comprising:(a) a luminescent alkaline earth metal halophosphate activated by Sb.sup.3+ and Mn.sup.2+ and having a color temperature of 2900-5000 K.;(b) a luminescent material activated by Eu.sup.2+ and having an emission maximum of 470-500 nm;(c) a luminescent rate earth metal metaborate activated by Ce.sup.3+ and Mn.sup.2+ and having a red Mn.sup.2+ emission, and(d) a luminescent aluminate activated by Ce.sup.3+ and having a garnet crystal structure absorbing blue radiation below 480 nm;(e) a green luminescing Mn.sup.2+ activated material having an emission maximum in the range from 510 to 535 nm. As a result of the addition of the material e the quantity of the material d can be limited so that color point differences among the lamps are avoided.