Discharge lamp with improved light distribution characteristics

摘要

Disclosed is a discharge lamp with enhanced vertical illuminance and accordingly improved light distribution characteristics that is easy to manufacture and suitable for mass production. For a discharge lamp in which a discharge path with a double helix configuration is formed or a discharge lamp in which a plurality of U-shaped tubes are placed on an arc tube holder to form a single tortuous discharge path, a width of a turning part 106 is specified so as to narrow spaces formed in an arc tube top part, or swelling parts are provided in a vicinity of the arc tube top part so as to narrow the spaces.