Patent ID: 8474985

Claim:
A discharge lamp lighting device for lighting a discharge lamp by supplying an AC current with a steady-state lighting frequency, and inserting an AC current with a low frequency that is lower than the steady-state lighting frequency, the device comprising: a lamp current control portion that generates, in synchronization with an input video signal, a control signal for controlling polarity reversal of the AC current with the steady-state lighting frequency and the AC current with the low frequency; and a lamp driving portion that drives the discharge lamp based on the control signal that is output by the lamp current control portion, wherein the lamp current control portion generates a control signal for a brightness reduction waveform with timing corresponding to a polarity reversal of the AC current with the steady-state lighting frequency, the lamp driving portion inserts a current reduction waveform into the AC current with the low frequency by decreasing a voltage applied to the discharge lamp based on the control signal for the brightness reduction waveform, and a reduction of the lamp current in the current reduction waveform is controlled so as to cause a reduction of the lamp brightness equivalent to a reduction of the lamp brightness resulting from the polarity reversal of the AC current with the steady-state lighting frequency.