LOW-PRESSURE MERCURY STEAM DISCHARGE LAMP

摘要

PURPOSE: To improve the reflectivity of the reflective layer of a low pressure mercury vapor discharge lamp. CONSTITUTION: A low pressure mercury vapor discharge lamp has an electric discharge container 1, which is made airtight and surrounds a discharge space 2 having enclosures of mercury and a rare gas. A manes of maintaining electric discharge 3 is provided in the discharge space 2. A part 5 of a surface 4 facing the discharge space 2 of the discharge container 1 has a reflective layer 6 of aluminum oxide particles which has large particles with a relatively large weight ratio and a central value of diameter 0.25μm-0.8μm and small particles with a relatively small weight ratio and a central value of diameter 0.01μm-0.02μm. The small particles of the reflective layer 6 are distributed among the large particles. A product of the central value of the particle size distribution across the whole, and the specified surface area of all the particles is taken as at least 4×10<-3> m<3> /kg.