Electric discharge lamp device

摘要

An electric discharge lamp device has a lighting start voltage storage circuit (320) for storing a lamp voltage immediately after the start of lighting of a lamp (2), and a change detection circuit (350) for detecting a change ( DELTA VL) in the lamp voltage by subtracting the lamp voltage immediately after the start of lighting of the lamp from the lamp voltage detected currently. The electric power supplied to the lamp (2) is controlled based upon the change ( DELTA VL) in the lamp voltage.