Patent ID: 8358069

Claim:
A method for generating light, comprising the steps of: providing a light source device including a discharge lamp with a discharge vessel having a deposit formed thereon and a discharge starting unit for starting discharge, the discharge starting unit including a pair of electrodes disposed apart from one another and arranged inside the discharge vessel of the discharge lamp and a power supply operative for supplying voltage between the pair of electrodes; irradiating the discharge vessel with a laser beam from a first laser oscillator, the laser beam having only an energy intensity sufficient in a period of time that nearly completely removes the deposit consisting of elements of an enclosure material in the discharge vessel, increase gradually on an inner face of the discharge vessel as a lighting time progresses or an aggregation substances of which are contents thereof; after the irradiating step, starting discharge in the discharge vessel by the discharge starting unit so that the power source supplies voltage between the pair of electrodes to generate ionized light emitting material; and after the starting discharge step, condensing the laser beam from a second laser oscillator at a condensing point located generally centrally within the discharge vessel containing ionized light emitting material to generate light.