High-pressure gas discharge lamp, and method of manufacturing same

The invention relates to high-pressure gas discharge lamps (HID [high intensity discharge] lamps or UHP [ultra high performance] lamps), in particular to mercury high-pressure lamps with mercury fill quantities of between approximately 0.05 and 0.5 mg/mm , which comprise at least one electrode with an electrode rod, which rod is provided at its end with a thickened, for example globular electrode portion. The invention further relates to a lighting unit with such a high-pressure gas discharge lamp and to a power supply unit for supplying the lamp with operating parameters adapted thereto, as well as to a method of manufacturing the lamp. A high-pressure gas discharge lamp (HID or UHP lamp, or in general lamps with mercury fillings of between approximately 0.05 and 0.5 mg/mm) is described with at least one electrode () which is provided with a thickened, for example globular portion () at its end lying inside a lamp vessel (). This portion is so dimensioned in dependence on operational parameters of the lamp and/or the diameter of the electrode rod that an electrode tip () forms itself independently at said portion during the first hours of operation. This tip grows from the portion until its free end starts melting. The electrode tip is self-adjusting in this manner, so that an optimum electrode interspacing is maintained throughout lamp life. Furthermore, a method of manufacturing such a lamp is described.