Improvement in Start Characteristics of Mercury-free Metal Halide Discharge Lamps for Automobiles.

We investigated the start characteristics (decreasing the breakdown voltage and increasing the luminous flux during run-up time) of mercury-free metal halide discharge lamps. Breakdown voltage of mercury-free metal halide discharge lamp could be reduced if the gas in the outer envelope is Xe or Xe/Ne. Adding indium iodide and supplying higher electrical power could increase luminous flux during run-up time. The run-up requirements in ECE regulation No. 99 can be achieved by supplying 90W of power to the lamp during run-up time.