| 摘要 |
<p>Luminescent material for use in crystal, incandescent or other lamps, consists of an oxysulphide of La, Y and/or Gd which is coactivated by Yb and Ho (which may be partly replaced by Tm) and is pref. produced by mixing (i) an oxide or decomposable salt of La, Y and/or Gd, (ii) oxide or decomposable salt of 2+ activators, esp. Yb and one of Ho, Tm or Er, (iii) S and alkali metal carbonate, and pref. (iv) a source for F ions (to provide lighter emission), esp. an alkali metal fluoride or NH4F, and firing, pref. at 1000-1100 degrees C. Pref. mol. ratio Yb and Er (if present): metal (La, Y and/or Gd), expressed as oxides, is 0.01 to 0.5:1 (0.025 to 0.3:1); and mol. ratio Ho and/or Tm: metal (as oxides) is 0.02 to 0.00005:1.</p> |
