Special Arrangement of Phosphor Particles in Screen for Optimization of Illuminance (lm m<sup>-2</sup>) of FL Tubes

Abstract

The performance of lighted FL tubes is severely influenced by the depth of the gap between phosphor screen on inner glass wall and positive column which is defined by Fvect ≥ Fphos. Fphos is vertical electric field of the surface bound electrons (SBE) on electric insulator in vacuum. The SBE on phosphor particles in the screen of the commercial FL tubes pushes back approaching electrons from phosphor screen to positive column. Naturally, there is the gap between positive column and phosphor screen. The depths of the gap ever study on the lighted FL tubes quantitatively. The depth by the gap by SBE is 3 x 10-3 m that gives rise to the slow build - up curve of illuminance from FL tube. Unexcited Hg atoms in the gap severely control the illuminance (lm m-2) of FL tubes. The reliable FL tubes should have the depth of the gap less than 2 x 10-4 m. The formation of the narrow gap requires the special arrangement of (a) the low voltage CL phosphor particles and (b) PL phosphor particles side by side. The coil-EEFL tubes in the narrow gap allow the Ar gas pressures (>7 x 103 Pa) for the high illuminance (>103 lm m-2) with nearly zero power consumption by the DC operation.