To effectively generate ozone and excited state oxygen in a discharge lamp to act on an object.SOLUTION: In the discharge lamp 10 provided with the arc tube 11 having the double tube structure, ultraviolet rays having a wavelength of 172 nm are irradiated to the surface of the arc tube 11 (the outer surface 50 S of the inner tube 50 and the inner surface 20 I of the outer tube 20) Reflector C emitting fluorescence having a wavelength of 250 nm is thinly applied with a substantially uniform thickness over the entire surface. As a result, both ultraviolet rays having wavelengths of 172 nm and 250 nm are radiated to the outside of the lamp from the entire outer surface 20 S of the outer tube 20 which is the radiation surface of the arc tube 11.BACKGROUND OF THE INVENTION【課題】放電ランプにおいて、オゾンと励起状態酸素を効果的に生成し、対象物に作用させる。【解決手段】二重管構造の発光管11を備えた放電ランプ10において、発光管11の表面(内側管50の外表面50Sと外側管20の内表面20I)に対し、波長172nmの紫外線を受けて波長250nmの蛍光を発する蛍光体Cが、表面全体に渡って略均一の厚さで薄く塗布されている。その結果、発光管11の放射面となる外側管20の外表面20S全体から波長172nm、250nmの紫外線両方がランプ外へ放射される。【選択図】図1
