Patent ID: 8749138

Claim:
In a metal halide lamp for producing mainly light of ultraviolet rays, said metal halide lamp comprising a lamp into which a rare gas and at least mercury and an iron are sealed to produce light with a high spectrum in ultraviolet rays, particularly, light with a wavelength of 350 to 380 [nm], in which said sealed iron is offered by iron iodide (FeI 2 ) and iron bromide (FeBr 2 ) as iron halide (FeX 2 ) and metal iron (Fe), when a quantity of the sealed iron is expressed such that A represents a quantity of metal iron (Fe) sealed into the lamp, B represents a quantity of iron iodide (FeI 2 ) sealed into the lamp and that C represents a quantity of iron bromide (FeBr 2 ) sealed into the lamp, respectively, the quantity A of said metal iron (Fe) falls within the range of 0.5 (B+C)≦A≦10.0 (B+C) [mol/cm 3 ], the quantity (B+C) of said iron halide (FeX 2 ) falls within the range of 1.0×10 −7 ≦(B+C)≦4.5×10 −7 [mol/cm 3 ], and a ratio {C/(B+C)} of said iron bromide (FeBr 2 ) in said ion halide (FeX 2 ) falls within the range of {C/(B+C)}=5 to 70 [%].