A new diagnostics of plasma electron temperature and plasma density is introduced with the observation of the light emission along the tube of external electrode fluorescent lamps. With two different methods operating an external electrode fluorescent lamp of outer diameter 4.0 ㎜ and length 860 ㎜ for the back-light source of 37-inch LCD-TVs, the lighting modes and the plasma properties are investigated. In the center balance operation, the light-emission propagates simultaneously from both sides of the high voltage electrodes to the center of the lamp, while in conventional operation the light-emission propagates from the one end of a high voltage to the other ground electrode. In the operation value of luminance 10,000~15,000 ㏅/㎡, the electron plasma thermal energy (kTe) is about 1.3~2.7 eV with the electron density (ne) is about (1.6~3.6)×10¹⁶ m^-3.

Keywords: 방전,플라즈마,플라즈마 진단,외부전극 형광램프(EEFL),LCD,백라이트(Backlight),Discharge,Plasma,Plasma diagnostics,External Electrode Fluorescent Lamp