Patent ID: 7468584

Claim:
Process for producing a discharge lamp having a silica glass discharge vessel in which a pair of electrodes is disposed and which is filled with at least 0.15 mg/mm 3 of mercury, argon (Ar), and halogen, comprising the steps of: measuring the relation b/a 1 between the emission intensity a 1 of argon (Ar) at a wavelength of 668 nm and the emission intensity b of OH radicals at a wavelength of 309 nm in a state of glow discharge of the discharge lamp; supplying hydrogen into the discharge vessel of the discharge lamp; measuring the relation c/a 2 between the emission intensity a 2 of argon (Ar) at a wavelength of 668 nm and the emission intensity c of OH radicals at a wavelength of 309 nm in the state of glow discharge of the discharge lamp; and fixing the difference c/a 2 −b/a 1 at a value in the range of 0.001 to 15.