| 摘要 |
PROBLEM TO BE SOLVED: To provide a light source for illumination in which the amount of radiation of ultraviolet rays is increased without adding specific constitution and decreasing the amount of irradiation of visible light. SOLUTION: A light source has an outer tube bulb 22 made of glass in which the coefficient of thermal expansionαis within the range of 20-70, the maximum transmission factor of the visible light and the ultraviolet ray having a wave length of 300-320 nm is 50% or more, and an arc tube 2 which is arranged within the outer tube bulb 22, in which a discharge medium is sealed, and visible light and ultraviolet ray are radiated by discharge. In the case that it is used as the light source for a luminaire with a photocatalyst medium function, for example, as a high pressure sodium lamp, photocatalyst activity is enhanced without decreasing the amount of irradiation of visible light.
|
