Patent ID: 8648549

Claim:
A lighting method for lighting a high pressure discharge lamp having an arc tube in which mercury is enclosed as a light-emitting material and in which a pair of electrodes are arranged, comprising the steps of: commencing lighting by applying a predetermined voltage to the pair of electrodes to cause dielectric breakdown to occur therebetween; performing lighting warm-up by, in an initial lighting interval from lighting commencement to constant power control at a rated power value Ps [W] of the high pressure discharge lamp, controlling a lamp power supplied to the high pressure discharge lamp according to a predetermined condition; and performing stable lighting to cause the high pressure discharge lamp to be lit stably by performing constant power control at the rated power value Ps [W], wherein in the lighting warm-up step, the lamp power is controlled according to the predetermined condition that a relational expression t [degrees C.]<=1.1 T [degrees C.] is satisfied, where t [degrees C.] is an electrode tip temperature in the initial lighting interval and T [degrees C.] is the electrode tip temperature during stable lighting.