Patent ID: 8339044

Claim:
A mercury-free high intensity discharge lamp comprising: a discharge vessel formed of a ceramic material and defining an interior space, wherein an aspect ratio of the discharge vessel is satisfied by 1<ITL/ID<4.5 where ITL is the inner total length of the discharge vessel and ID is the inner diameter of the discharge vessel; at least one electrode extending into the discharge vessel; and a mercury-free and scandium-free ionizable fill disposed within the interior space and sealed within the vessel, wherein said fill is free of elemental mercury and mercury compounds, and wherein the ionizable fill is further free of elemental zinc, said fill including: (a) an inert gas sealed within said vessel, said inert gas comprising at least about 95% Xe, said inert gas present at a cold fill pressure of from about 3 to about 15 bar; and (b) a halide component, said halide component comprising: (i) sodium halide; (ii) thallium halide; and (iii) at least one rare earth halide, wherein the at least one rare earth halide comprises holmium halide.