Lighting circuit for and lighting method of high-pressure discharge lamp

摘要

It is an object of the present invention to provide a lighting circuit for and a lighting method of a high-pressure discharge lamp whereby remarkable reduction in illuminance maintaining rate can be avoided by reducing variation in inter-electrode distance in the beginning of usage without modulating a lighting frequency. The object can be achieved by a lighting circuit (10) configured to light a high-pressure discharge lamp (28) by supplying an alternating lamp current (A L ), which includes at least one pulse current (A P1 ) superimposed on the former half of each half period of a base lamp current (A LB ) and at least two pulse currents (A P2 and A P3 ) superimposed on the latter half of each half period, to the high-pressure discharge lamp (28).