Discharge lamp with specific amounts of halogen, oxygen, hydrogen and carbon

Method of producing a discharge lamp comprising the steps of:

• providing a silica glass discharge vessel having a discharge space,
• locating a pair of opposed electrodes located in the discharge vessel, and
• filling the discharge vessel with at least 0.15 mg/mm3 of mercury and a rare gas having argon as a main component, and bromine in an amount in a range of 2×10−4 μmole/mm3 to 7×10−3 μmole/mm3,
• setting amounts of oxygen, hydrogen and carbon which are present in the discharge space of the discharge vessel so as to meet the following conditions (1) to (4) when a direct current of 5 mA is fed between the above described electrodes and a glow discharge produced:
• 1.0×10−4≦b/a≦1.2×10−1 Condition (1)
• c/a≦1.4×10−1 Condition (2)
• d/a≦1.2×10−2 Condition (3)
• e/a≦1.4×10−2 Condition (4)
• where a is the emission intensity of the argon with a wavelength of 668 nm, b is the emission intensity of OH with a wavelength of 309 nm, c is the emission intensity of hydrogen (H) with a wavelength of 656 nm, d is the emission intensity of C2 with a wavelength of 517 nm, and e is the emission intensity of CH with a wavelength of 431 nm.