Luminescent lead-activated alkaline earth metal rare earth metal borates and mercury vapor discharge lamp containing the same

摘要

Luminescent lead-activated alkaline earth metal rare earth metal borates having compositions defined by the formula Me.sub.1-p Pb. sub.p La. sub.1-x-y Y.sub.x Gd.sub.y BO.sub.4, where Me represents strontium and/or calcium, where 0.005 ≦p≦0.30 and 0≦x≦0.1, and where O≦y≦0.5 when at least 75 mole% of Me is Ca and O. ltoreq. y≦0.1 when less than 75 mole% of Me is Ca. The borate may be used in the luminescent screen of low-pressure mercury vapor discharge lamps.