| 摘要 |
PROBLEM TO BE SOLVED: To improve a light emitting efficiency of a fluorescent lamp with an external electrode. SOLUTION: The fluorescent lamp with an external electrode 20 is composed of an almost cylinder-shaped glass tube 21 in which, xenon gas is enclosed, and a pair of electrodes 22a, 22b stuck on the outer periphery of the glass tube so as to face each other. The thickness of respective electrodes 22a, 22b in the direction of the width is the thickest at the central area and becomes thinner as it is headed to the end part. By the above, the strength of electric field (X) is the weakest at the central area and becomes stronger as it is headed to the end part. The resistance of the electrodes 22a, 22b in the direction of the width at respective positions are made to change according to the thickness of the electrodes 22a, 22b in the direction of the width so as to correspond to the strength of the electric field (X). Namely, the wall thickness is thick and the resistance is low at the central area of the respective electrodes 22a, 22b, and the wall thickness becomes thin and the resistance becomes higher as it is headed to the end part. By the above, the amount of the current in the direction of the cross section of the glass tube 21 becomes uniform and unevenness of light emission at a fluorescent film 24 is prevented. COPYRIGHT: (C)2004,JPO
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