Patent ID: 8564200

Claim:
A metal halide lamp ( 1 ) comprising a ceramic discharge vessel ( 3 ), which discharge vessel ( 3 ) encloses a discharge volume ( 11 ), comprises two electrodes ( 4 , 5 ), and contains an ionizable gas filling, the ionizable gas filling comprising one or more components selected from the group consisting of LiI, NaI, KI, RbI, CsI, MgI 2 , CaI 2 , SrI 2 , BaI2, ScI 3 , YI 3 , LaI 3 , CeI 3 , PrI 3 , NdI 3 , SmI 2 , EuI 2 , GdI 3 , TbI 3 , DyI 3 , HoI 3 , ErI 3 , TmI 3 , YbI 2 , LuI 3 , InI, TlI, SnI 2 and ZnI 2 , wherein the concentration h of the respective components in the discharge vessel ( 3 ) in μg/cm 3 fulfill the equation: log h=A/T cs 2 + B/T cs + C +log z , wherein T cs is the coldest spot temperature of discharge vessel ( 3 ) in Kelvin during nominal operation of the lamp ( 1 ), wherein A, B and C are defined as follows: Component A*10 −6 B*10 −3 C LiI −0.51 −5.88 7.16 NaI −1.30 −5.82 6.99 KI −2.51 −3.48 5.66 RbI −2.04 −4.95 6.48 CsI −1.40 −5.72 7.13 MgI 2 −1.92 −4.40 8.20 CaI 2 −3.45 −5.99 6.83 SrI 2 −1.99 −9.33 8.05 BaI 2 −2.15 −10.00 8.47 ScI3 −17.70 18.76 0.16 YI 3 −7.96 0.43 6.41 LaI 3 −4.24 −4.66 6.98 CeI 3 −3.15 −7.37 9.36 PrI 3 −1.98 −7.86 8.43 NdI 3 −4.29 −4.42 6.58 SmI 2 −1.62 −11.20 9.71 EuI 2 −1.95 −10.50 8.95 GdI 3 −9.69 4.26 3.62 TbI 3 −9.41 4.09 3.59 DyI 3 −11.90 6.42 4.68 HoI 3 −9.48 3.15 5.61 ErI 3 −12.10 6.54 5.46 TmI 3 −3.12 −5.25 7.64 YbI 2 −1.33 −10.10 8.45 LuI 3 −9.00 3.37 5.38 InI −1.30 −2.02 6.11 TlI −1.36 −2.92 7.01 SnI 2 −1.99 −1.14 6.39 ZnI 2 −2.58 0.65 5.23 and wherein T cs is at least 1200 K and z is between 0.001 and 2, wherein the ionizable gas filling further comprises at least one of dysprosium iodide, cerium iodide or indium iodide.