| 摘要 |
PROBLEM TO BE SOLVED: To maintain stable arc while maintaining a projection of an electrode tip in an ideal condition, even if the lamp is lit with a lamp power of 70% or less of the rated electric power. SOLUTION: In a high-pressure discharge lamp lighting device used in an alternating current lighting method, having a discharge vessel with a pair of electrodes arranged in opposition to each other with a spacing of 2.0 mm or more, each electrode having a projection formed at a tip end thereof, and mercury of 0.20 mg/mm<SP>3</SP>and a halogen being enclosed in the discharge vessel, base lighting for supplying base current having a specific frequency and boost lighting for supplying boost current Ib(A) having larger electric current value than that Ia(A) of the base current are carried out alternatively, during a period of a low electric power lighting mode for making to light with power of 70% or less of a rated power consumption. By carrying out the boost lighting, there is no fear of a plurality of secondary projections generated, and thus, stable arc can be realized even in the low electric power lighting mode with power of 70% or less of a rated power. COPYRIGHT: (C)2011,JPO&INPIT |
