Patent ID: 7245081

Claim:
A high-intensity discharge lamp including an arc tube, the arc tube comprising: a translucent ceramic discharge chamber that defines a discharge volume, said chamber having a pair of end sections provided at both ends of a central section; a pair of feedthroughs, each of said feedthroughs being hermetically sealed within one of said end sections respectively; and a pair of electrodes, each of said electrodes comprising a tip that extends towards the central section and is connected to one of said feedthroughs, wherein the discharge chamber is filled with a discharge medium including a metal halide and a starting gas, said metal halide comprising at least halides of Na, Tl, and Tm, and wherein the ratio (MTm/M) of the mass MTm of Tm halide to the total mass M of said metal halide is within a range of about 0.4≦MTm/M≦0.9.