DIMMING UNIFORMITY ENHANCEMENT PLATES

摘要

Dimming uniformity enhancement plates are provided in combination with a differential driver for providing uniform illumination of long serpentine fluorescent lamps. The differential driver applies sinusoidal pulses to opposite ends of the lamp for causing ionization and arcing in a well known manner. The sinusoidal signals are of opposite phase. Light intensity is controlled via pulse frequency. In order to ensure good uniformity at low lighting levels, a pair of foil plates are attached to the centre section of the tube lamp. The high voltage pulses are applied to the two plates so that the voltage applied to the plates is 180 DEG out of phase and each plate is also 180 DEG out of phase with the nearest tube end. This results in a distribution of accelerating potential to the lamp arc throughout the tube length.