Patent ID: 8089215

Claim:
A discharge lamp lighting device, comprising: a DC power source for outputting a DC output power; an inverter for inverting the DC power outputted from the DC power source at a predetermined inversion time interval to supply a square wave AC power to a discharge lamp; and a controller for controlling the output power from the DC power source, wherein the controller performs a synchronous operation for temporarily increasing the output power from the DC power source in an output temporarily increasing period existing immediately before and/or immediately after every inversion operation of the inverter, wherein the controller controls the DC power source such that DC power outputted during a period other than the output temporarily increasing period in a power increasing period is greater than the DC output power outputted during the period other than the output temporarily increasing period in a rated power period, the rated power period being a period during which a rated power is supplied to the discharge lamp and the power increasing period being a period from start-up of the discharge lamp to an onset of the rated power period, and wherein the controller controls the DC power source such that at least one of an increment of the output power for the output temporarily increasing period and a length of the output temporarily increasing period is less in at least a part of the output increasing period than in the rated power period.