Patent ID: 7057349

Claim:
A lighting device comprising: (A) a metal halide discharge lamp which essentially permits disusing mercury, including: (a) a refractory and light-transmitting hermetic vessel; (b) a pair of electrodes fixed to said hermetic vessel; and (c) a discharge medium sealed in the hermetic vessel and containing a first halide and a second halide, (i) said first halide being a halide of at least one metal which emits a visible light and being a halide of at least one metal selected from the group consisting of sodium, scandium and a rare earth metal, and (ii) said second halide having a vapor pressure less than 5 atmosphere during lighting so as to act as a buffer gas to maintain a lamp voltage and being a halide of metal which emits a visible light less than that emitted by the metal of the first halide; and (B) an electronic lighting circuit configured to supply current to said metal halide lamp.