Patent ID: 8310174
Filing Date: 2012-11-13
Classification: H01J

Abstract:
1. 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, wherein the lighting warm-up step includes: a relational expression Ia [A]*Va [V]=Pa [W] is satisfied, and the second sub-step is performed in the lower-power lighting interval; 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 the initial lighting interval includes a lower-power lighting interval in which lighting is sustained at a constant power value Pa [W] that is lower than the rated power value Ps [W].