Fluorescent lamp with phosphor having coated phosphor particles

A fluorescent lamp comprising:

• a light transmission glass tube;
• a phosphor layer formed on the inner wall of the light transmission glass tube and including phosphor particles;
• gases filled in the light transmission glass tube and including a mercury gas and a rare gases;
• and
• a means, arranged in the light transmission glass tube, for generating positive column discharge in the gas;
• wherein said phosphor particles are charged positive and smaller than 3.0 .mu.C per gram as measured when in contact with soda lime glass beads each having a particle size of 200-500 .mu.m, and the phosphor particles are coated with at least one oxide of a substance selected from the group consisting of Mg, Ca, Sr, Ba, La, Eu, Y, Tm, Dy, Nd, Cd, Zn, Co, Pb, Ni, Sc, Hg, Cu, Mo, In, Hf, Ga, Ce, Cr, Fe, Zr, As, B, Mn, Tl, Bi, Ge, Sn, Ta, P, V and Nb.

A fluorescent lamp comprising:

• a light transmission glass tube;
• a phosphor layer formed on the inner wall of the light transmission glass tube and including phosphor particles;
• gases filled in the light transmission glass tube and including a mercury gas and a rare gases;
• and
• a means, arranged in the light transmission glass tube, for generating positive column discharge in the gas;
• wherein said phosphor particles are charged positive and larger than -0.5 .mu.C per gram and less than 2.5 .mu.C per gram when they are brought into contact with reduced iron powder having a particle size of 44-74 .mu.m, and the phosphor particles are coated with at least one oxide of a substance selected from the group consisting of Mg, Ca, Sr, Ba, La, Eu, Y, Tm, Dy, Nd, Cd, Zn, Co, Pb, Ni, Sc, Hg, Cu, Mo, In, Hf, Ga, Ce, Cr, Fe, Zr, As, B, Mn, Tl, Bi, Ge, Sn, Ta, P, V and Nb.