The Effects of Electrode Configuration on the Luminance and Luminous Efficacy of Mercury-Free Flat Fluorescent Lamp

To obtain highly efficient and stable discharges in mercury-free flat fluorescent lamps (MFFLs), the effects of the main electrode configuration on the electro-optical characteristics such as the operating voltage margin, luminance, and luminous efficacy are investigated. The spatiotemporal characteristic of the infrared emission from discharges in different electrode configurations (conventional coplanar, counter, and combination discharges) is also studied with an intensified charge-coupled device camera to see the differences with the electrode configuration variation. The MFFL having the combination electrode configuration with Ne-30% Xe gas mixture and a total pressure of 13.3 kPa showed high luminance from 3102 to 22 067 cd/m 2 and high luminous efficacy from 49 to 93.5 lm/W for the warm white daylight with a color coordinate of (0.36, 0.36).