| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultraviolet discharge lamp in which an illuminance difference in an axial direction of a lamp is reduced by regulating a phosphor amount. SOLUTION: A transparent glass arc tube 11 formed of soda lime glass containing 10% or larger of a sodium oxide in 100% of a base material obtains a transmittance ratio of 80% or higher in a wavelength of 320-340 nm which is required for an ultraviolet discharge lamp. The arc tube 11 has, for instance, a tube diameter D of 38 mm and a tube length L of 2,367 mm, and in the arc tube 11, there are arranged a pair of electrodes 121, 122 opposed to each other, and a noble gas such as argon gas or the like and the mercury of a fixed amount are enclosed. Then, an inner wall of the arc tube 11 is coated under a condition of N/S=2<(N/S)<7 when the phosphor amount having a peak of conversion efficiency between 300-340 nm after a mercury spectrum 253.7 nm is converted is N(mg) and an inner surface area to be coated is S(cm<SP>2</SP>). COPYRIGHT: (C)2011,JPO&INPIT |
