U.S. Philips Corporation

Antonius M Seuter

Petrus F Van Den Boom

Johannes G Verriet

A low-pressure mercury vapor discharge lamp comprising a glass discharge envelope (1) in which during operation of the lamp a discharge is present and which contains mercury and a rare gas, at least a part of the inner wall of the discharge envelope being provided with a thin at least substantially homogeneous continuous transparent layer (4) which is resistent to the action of the discharge. According to the invention, this transparent layer (4) contains an oxide of at least one of the groups comprising yttrium, scandium, lanthanum, gadolinium, ytterbium and lutetium.

Low-pressure mercury vapor discharge lamp

Luminescent bivalent europium-activated barium borophosphates having defined compositions by the formula Ba.sub.3-p Eu.sub.p BP.sub.3 O.sub.12, where 0.01.ltoreq.p.ltoreq.0.50. A quantity of not more than 20 mole % of the Ba may be replaced by Sr and/or Ca. The borophosphate can be used in luminescent screens of low-pressure mercury vapour discharge lamps.

Luminescent bivalent europium-activated barium borophosphate and

A luminescent material having the eulytine crystal structure and a composition defined by Ca.sub.3-x-y-p Me.sub.x Sn.sub.p Ln.sub.1+y-q-r A.sub.q Sb.sub.r (PO.sub.4).sub.3-y (SiO.sub.4).sub.y, wherein Me is Sr and/or Ba, Ln is Y, La, Gd and/or Lu, and A is Ce and/or Tb and wherein 0.ltoreq.x.ltoreq.2.5, 0.ltoreq.y.ltoreq.0.5, 0.ltoreq.P.ltoreq.0.2, x+y+p.ltoreq.2.5, 0.ltoreq.q.ltoreq.1+y-r, 0.ltoreq.r.ltoreq.0.5, p+q+r.noteq.0.

Luminescent materials and discharge lamp containing the same

Terbium-activated luminescent material with garnet crystal structure satisfying the formula

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Eindhoven, Netherlands

Antonius M Seuter