Luminescent screen and low pressure mercury vapor discharge lamp containing the same

A luminescent screen, comprising a luminescent metaborate, having a monoclinic crystal structure provided on a support, characterized in that the metaborate has a composition defined by the formula

• (Y, La).sub.1-x-y-z Ce.sub.x Gd.sub.y Tb.sub.z (Mg, Zn).sub.1-p Mn.sub.p B.sub.5 O.sub.10,
• wherein,
• if y=z=p=0, it holds that 0.01.ltoreq.x.ltoreq.1.0,
• if z=p=0, it holds that
• 0.01.ltoreq.x.ltoreq.1-y
• 0.02.ltoreq.y.ltoreq.0.80,
• if p=0, it holds that
• 0.01.ltoreq.x.ltoreq.1-y-z
• 0.ltoreq.y.ltoreq.0.98
• y+z.ltoreq.0.99
• 0.01.ltoreq.z.ltoreq.0.75,
• if z=0, it holds that
• 0.01.ltoreq.x.ltoreq.1-y
• 0.ltoreq.y.ltoreq.0.99
• 0.01.ltoreq.p.ltoreq.0.30.
• and if both p.noteq.0 and z.noteq.0, it holds that
• 0.01.ltoreq.x.ltoreq.1-y-z
• 0.ltoreq.y.ltoreq.0.98
• 0.01.ltoreq.z.ltoreq.0.75
• y+z.ltoreq.0.99
• 0.01.ltoreq.p.ltoreq.0.30 and wherein when p=0 and x+y+z=1, up to 20 mole % of the B is replaceable by Al and/or Ga;
• when z=0 and x+y=1, up to 20 mole % of the B is replaceable by Al and/or Ga;
• and when both p.noteq.0 and z.noteq.0 and x+y+z=1, up to 20 mole % of the B is replaceable by Al and/or Ga.