Abstract: A low-pressure mercury vapor discharge lamp having a very satisfactory color rendition, (R(a,8).gtoreq.85), a color temperature of 2300-3300 K and a color point on or near the Planckian curve. 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+ having a color temperature of 2900-5000 K;b. a luminescent material activated by Eu.sup.2+ with an emission maximum van 470-500 nm and a half-value width of at most 90 nm, andc. a luminescent rare earth metal metaborate activated by Ce.sup.3+ and Mn.sup.2+, having a fundamental lattice Ln(Mg,Zn,Cd) B.sub.5 O.sub.10, in which Ln represents the elements Y, La and/or Gd, which borate has red Mn.sup.2+ emission.Further, the lamp is provided with means for absorbing blue radiation having wavelengths below 480 nm. Preferably, the luminescent layer further contains:d. a luminescent material activated by Tb.sup.3+ which exhibits green Tb.sup.3+ emission.

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.).

Abstract: A low-pressure mercury vapor discharge lamp having a very satisfactory color rendition (R(a,8).gtoreq.85) and having a color temperature of at least 3200 K. and a color point located on or near the Planckian locus. The lamp is provided with a luminescent layer comprising:a. a luminescent alkaline earth metal halophosphate activated by Sb.sup.3+ or by Sb.sup.3+ and Mn.sup.2+b. a luminescent material activated by Eu.sup.2+ and having an emission maximum at 470-500 nm and a half-width value of at most 90 nm andc. a luminescent rare earth metal metaborate activated by Ce.sup.3+ and Mn.sup.2+ and having a fundamental lattice Ln(Mg,Zn,Cd)B.sub.5 O.sub.10, where Ln represents the elements Y, La and/or Gd, which borate has a red Mn.sup.2+ emission.

Abstract: A low-pressure mercury vapor discharge lamp having a satisfactory color rendition (Ra.gtoreq.80), a color temperature of 2800.degree. K. or higher and a color point on or near the Planckian locus. The lamp is provided with a luminescent layer (4) which comprisesa. a luminescent rare earth metal metaborate activated by Ce and Mn and having a fundamental lattice Ln(Mg,Zn,Cd)B.sub.5 O.sub.10, where Ln represents the elements Y, La and/or Gd, which borate exhibits red Mn emission,b. a luminescent material activated by Tb.sup.3+ and having green Tb.sup.3+ emission,c. at least one luminescent halophosphate of the group which comprises the calcium halophosphates emitting white light, activated by Sb.sup.3+ and Mn.sup.2+ and having a color temperature of at least 2900.degree. K. and blue-luminescing calcium halophosphate activated by Sb.sup.3+.The lamps yield a satisfactory rendition of deep red colors (R9.gtoreq.60) and have a high luminous flux and a high maintenance of the luminous flux during the life.

Abstract: A luminescent screen provided with a luminescent layer formed on a carrier, which layer comprises an aluminate and/or a gallate of strontium and/or barium activated by bivalent europium or by trivalent chromium. The aluminate and/or gallate has an orthorhombic crystal structure with a space group P.sub.nnm and has a composition defined by the formula Me.sub.2-x Eu.sub.x A.sub.6-y Cr.sub.y O.sub.11 (Me=Sr, Ba and A-Al, Ga).An advantageous application of such a luminescent screen is found in low-pressure mercury vapor discharge lamps.