Patent ID: 8525431

Claim:
A lighting apparatus for a high-pressure discharge lamp, comprising: an electric discharge container that comprises of quartz glass and contains a pair of counter electrodes; and a power supply unit that supplies an AC current to the high-pressure discharge lamp, wherein the power supply unit has a normal power lighting mode and a modulated power lighting mode that supplies current having a power less than a power in the normal power lighting mode, wherein the modulated power lighting mode supplies a rectangular AC current having a first term and a second term, wherein a mean high-frequency current value supplied to a first electrode at an anode phase is greater than a mean current value supplied to a second electrode at the anode phase in the first term, and wherein a current is supplied to the second electrode at the anode phase for a term longer than the half-cycle period in the second term, the current being lower than the mean high-frequency current value supplied to the first electrode.