High pressure mercury vapour discharge lamp with reduced sensitivity to variations in operating parameters

摘要

A high pressure mercury vapor discharge lamp is provided. The lamp has a discharge vessel (3) formed from heat-resistant material. At least two electrodes (5) extend into the discharge vessel (3) and are electrically connected to external current supply leads (9). The lamp has a fill in the discharge vessel (3) which includes a noble gas, mercury and an additive composition of metal halides. This additive composition of metal halides comprises an alkali metal halide, wherein the alkali metal halide is a sodium halide, a cesium halide, or a mixture of sodium halide and cesium halide, at least one halide of a metal providing a line emission, at least one halide of a rare earth metal providing an emission in the purple spectral range, at least one halide of a rare earth metal providing an emission in the green spectral range.