U.S. Philips Corporation

Joseph Rutten

Johannus G Verlijsdonk

Johannes T Van Kemenade

Bruno M Smets

Gerardus P Hoeks

Luminescent Eu.sup.3+ -activated alkaline earth metal-rare earth metal silicate, which is defined by the formula Ba.sub.2 Gd.sub.2-x-y Y.sub.x Eu.sub.y Si.sub.4-z Ge.sub.z O.sub.13, in which O.ltoreq.x.ltoreq.1.3, 0.01.ltoreq.y.ltoreq.1.0 and O.ltoreq.z.ltoreq.4, luminescent screen provided with such a silicate and low-pressure mercury vapor discharge lamp provided with such a screen.

Luminescent Eu.sup.3+ -activated silicate, luminescent screen provided

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.

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Eindhoven, Netherlands

Joseph Rutten