JPS57207677A - Fluorescent lamp - Google Patents

Abstract

PURPOSE: To provide a fluorescent lamp having reduced starting voltage, by using a specific fluorescent layer consisting of a blue light-emitting fluorescent material composed of a halo-borophosphate activated with Eu²⁺, etc., a green light-emitting fluorescent material composed of an alumino phosphate activated with Ce and Tb, and a red light-emitting fluorescent material composed of yttrium oxide activated with Eu³⁺.

CONSTITUTION: The objective lamp has a fluorescent layer consisting of (A) a blue light-emitting fluorescent material composed of Eu²⁺ -activated chlorophosphate fluorescent material of formulaI (M and M' are Sr, Ca or Ba) or Eu²⁺- activated halo-borophosphate fluorescent material of formulaII(X is Cl, F or Br; 2.7≤×≤3.3; 0.5≤y≤1.5; 0.10≤a≤0.50; 0.01≤b≤0.50; 0.001≤p≤0.2), (B) a green light-emitting fluorescent material composed of Ce-and Tb-activated aluminophosphte of formula III (Re is Y, La or Gd; A is Li, Na, etc.; 0<c, 0<d, 5×10^-2≥e≥1×10^-4, 0<(c+d+3e)<1; 0<q; 0<r), and (C) a red light-emitting fluorescent material composed of Eu³⁺-activated yttrium oxide of formula IV. The mixing ratios of (A):(B):(C) are preferably (2W40wt%):(15W75%): (17W68%).

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