High-pressure discharge lamp light source device having a power supply device with a switching state for switching from a direct current drive in a standby state to an alternating current drive in an operating state and projector

A projector having means for projecting images comprising a high-pressure discharge lamp, wherein the high-pressure discharge lamp comprises a discharge container made of quartz glass and containing a pair of opposed electrodes, mercury in a quantity of at least 0.20 mg/mm3, halogen in a range of 10−6 mol/mm3 to 10−2 μmol/mm3, and a prescribed amount of rare gas sealed therein and a power supply device having an operating state for operating the high-pressure discharge lamp and a standby state, said power supply device being adapted to supply rectangular wave alternating current in said operating state and having a direct current drive which is adapted to provide direct current in said standby state of at most 0.5×P (W) with respect to the maximum operating power P (W) during steady operation except for an initial operation period immediately after starting an operation by means of the direct current drive, and a switching state in which is performed a switching from the direct current drive to an alternating current drive in case of operation with a higher power than 0.5×P (W) after said operation with a power of at most 0.5×P (W), and wherein at least one of the power and frequency of said alternating current is gradually increased and a transition to the steady-state lighting is performed.