Characteristics of positive column contraction of xenon fluorescent lamps with two-pairs of electrodes in pulsed discharge

Summary form only given, as follows. Xenon emits strong radiation in the ultra-violet (UV) region and hence is one of the most promising candidates as an alternative to mercury. Nevertheless, the efficiency with which UV radiation is emitted from a xenon discharge is in general lower than that of mercury. Besides, the positive column of a xenon discharge tends to contract at high current density and the intensity of the phosphor-converted emissions from a contracted discharge is very low. In this study, the relations between the contraction process and the pulse width used in the pulsed discharge are discussed. Moreover, two pairs of electrodes are placed in a xenon fluorescent lamp so that the positive column in a diffused state occupies a larger volume for improving the luminance and the efficiency. The lamps were sustained by pulsed discharge. In the diffused state, as the current was gradually increased, the contraction of the positive column occurred at a specific value. Under all conditions, the luminous intensity of the phosphor-converted emissions reached a maximum prior to the transition of the state of the discharge from diffuse to contraction. When the pulse width was decreased, the luminance and efficiency of the lamps of any electrode type was increased.