Patent ID: 8317339

Claim:
A discharge lamp lighting device comprising: a discharge lamp driving unit that supplies an AC driving current to a discharge lamp to drive the discharge lamp; a current detecting unit that detects the AC driving current supplied to the discharge lamp; and a control unit that controls the discharge lamp driving unit, the control unit controlling the discharge lamp driving unit after a predetermined time from the start of lighting driving operation of the discharge lamp on the basis of the behavior of the AC driving current detected by the current detecting unit at the predetermined time from the start of lighting driving operation of the discharge lamp, and wherein the control unit performs a first determination processing for determining whether or not a first period, for which an absolute value of an average current value of the AC driving current at a time of first polarity is equal to or larger than a first threshold value and an absolute value of an average current value of the AC driving current at a time of second polarity is equal to or larger than a second threshold value, continues for a first reference time or more and controls the discharge lamp driving unit after the predetermined time from the start of lighting driving operation of the discharge lamp on a basis of a length of a first time from the start of lighting driving operation of the discharge lamp to a start of the first period when it is determined that the first period continues for the first reference time or more in the first determination processing.