U.S. Philips Corporation

Evert D Schutten

Johannus G Verlijsdonk

Cornelis Huiskes

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:

Fluorescent lamp

A luminescent screen provided with a zirconium- and/or terbium-activated silicate having an apatite crystal structure according to the formula

Luminescent screen and low-pressure mercury vapor discharge lamp

A luminescent screen provided with a terbium-activated silicate having a cuspidine crystal structure according to the formula Y.sub.4-x-z-p Ca.sub.x M.sub.z.sup.II Tb.sub.p Si.sub.2-y Al.sub.y O.sub.7+x+z+y N.sub.2-x-z-y. In this formula M.sup.II is at least one of the elements Mg, Sr and Ba. The yttrium can be replaced up to at most 50 mol. % by Gd and/or La. It further holds that:

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Roosendaal, Netherlands

Evert D Schutten