Glass tube of high dielectric constant and low dielectric loss for external electrode fluorescent lamps

Abstract

A glass tube of aluminosilicate glass, with high dielectric constant K∼6.0 and low dielectric loss tan δ∼8.0× 10-4, was investigated for the external electrode fluorescent lamps (EEFLs) of a dielectric barrier discharge. Compared with conventional EEFLs made out of borosilicate glass tubes with K∼ (4.9-5.3) and tan δ∼ (2.3-2.4) × 10-3, the efficiency of the aluminosilicate EEFL increases by 15%-25% even at high luminance above 20 000 cd/ m2 and the pinhole stability of the aluminosilicate EEFL also improves remarkably. In a soda-lime glass EEFL with a high dielectric loss tan δ∼7.0× 10-3, the luminance and pinhole stability deteriorate even with a high dielectric constant K∼7.2 at room temperature, because the value of tan δ escalates as the temperature on the external electrode increases due to the dielectric heat dissipation. © 2007 American Institute of Physics.