Patent ID: 7253568

Claim:
A high pressure discharge lamp lighting apparatus having a high pressure discharge lamp in which a pair of electrodes is arranged so as to face each other at an interval of 2 mm or less in an arc tube which is made of quartz glass, and mercury of 0.16 mg/mm 3 or more, rare gas, and halogen of 1×10 −6 to 1×10 −2 μmol/mm 3 is enclosed, and a power supply apparatus supplying direct current to the discharge lamp, wherein the power supply apparatus superimposes an alternating current component on the direct current and impress the superimposed current to the discharge lamp, wherein a frequency of the alternating current component is 40 to 5000 Hz. and 0.05≦(Imax−Imin)/IDC≦2 wherein Imax represents a maximum current value of the alternating current component, Imin represents a minimum current value of the alternating current component and IDC represents direct current value.