| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp which prevents a deterioration of a tubular bulb because a probability of rare gas ion or mercury ion being implanted on the bulb surfaces of external electrodes is lowered by expanding an electrode area on a non-irradiating surface side, reduces a discharge starting voltage, increases a light volume by expanding an emitting area on an irradiating side, and further improves a discharge delay by shortening a distance between the external electrodes on non-irradiating side, and also to provide a lighting system using the lamp. SOLUTION: The discharge lamp is formed of the tubular bulb (2) which at least one or more kinds of rare gases, argon, krypton, xenon and neon, or a rare gas and mercury are sealed in with both ends blocked and a phosphor film (3) formed on the inner surface thereof, and of a pair of the external electrodes (4), (5) disposed on the external surfaces of both ends in a tube axis direction of the tubular bulb (2). The areas of the irradiating surface sides of the tubular bulb (2) in the electrodes (4), (5) are made smaller that those of the non-irradiating surface sides.
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