Abstract: This invention provides a small metal halide lamp which has a power input of 100 W or less, provided with: an arc tube having a pair of electrodes spaced apart from each other and containing a rare gas, mercury, sodium halide and scandium halide therein; and an envelope for housing the arc tube. The mixing ratio of sodium halide to scandium halide based on weight is 3:1 to 10:1, and the total content of the sodium halide and the scandium halide is 10 to 40 mg per unit volume (cc) of the arc tube. At least one phospor selected from the group consisting of a manganese-activated magnesium fluorogermanate phosphor and a cerium-activated yttrium aluminate phosphor is applied to the inner surface of the envelope. In addition, a green-emitting phosphor is preferably coated on the inner surface of the envelope.

Abstract: A high pressure metal vapor discharge lamp including an arc tube having at least a main electrode at each end thereof, a fill sealed in the arc tube, including mercury, metal halide and starting gases selected from the group consisting of Ar, Kr and Xe, a radioactive source material, impregnated with a radioactive substance having a half-life less than 1.times.10.sup.4 years, sealed in the arc tube and a circuit including a conventional low voltage mercury lamp ballast and a glow starter for starting the arc tube.

Abstract: A high pressure metal vapor discharge lamp including an arc tube having opposed ends at which are provided respective main electrodes and a fill including mercury and a starting gas, a radioactive source material including a radioactive substance having a half-life less than 1.times.10.sup.4 years sealed in the arc tube, an outer tube enclosing the arc tube and a circuit for starting the arc tube.

Abstract: A high pressure discharge lamp including discharge tube having at least two electrodes at opposite ends thereof, an outer bulb housing the discharge tube, a circuit for starting the discharge tube and a glow starter which is covered with a heat shield member and disposed between the discharge tube and the outer bulb.

Abstract: In a discharge lamp comprising a sintered electrode comprising a high temperature melting metal such as tungsten, molybdenum, tantalum or mixtures thereof as a main ingredient of the sintered electrode and an electron emissive material of an alkaline earth metal or compound thereof, the sintered electrode further comprising at least one oxide of a metal selected from the group consisting of yttrium, zirconium and aluminum.