Metal halide lamp maintaining a high lumen maintenance factor over an extended operation period

摘要

A prescribed amount of tin halide is sealed in the arc tube of a metal halide lamp wherein a given amount of metal halide including a target amount of halogen and at least a predetermined amount of rare earth metal is sealed in the arc tube thereof to maintain a high lumen maintenance factor for an extended operation period. The prescribed amount of tin halide is preferabley within 4.6∼234 mol% of the predetermined amount of rare earth metal.