| 摘要 |
PROBLEM TO BE SOLVED: To provide an excimer discharge lamp generating vacuum ultraviolet light and suppressed in lowering of transmittance over a long period of time thereby to be suppressed in illuminance deterioration at a lighting initial period.SOLUTION: An excimer discharge lamp includes: a light emitting tube that has both ends sealed by a sealing part and is formed of sapphire; and a pair of electrodes disposed to be apart from each other via a tube wall of the light emitting tube. Light emitting gas is sealed in the light emitting tube, and at least one of the pair of electrodes is provided along an outer peripheral surface of the light emitting tube. In sapphire forming the light emitting tube, the total concentration of impurities relating to three kinds of Ti, Fe and Mn is 5 ppm or less.SELECTED DRAWING: Figure 1 |
