HIGH INTENSITY DISCHARGE LAMPS, ARC TUBES AND METHODS OF MANUFACTURE

摘要

A tipless arc tube (12) for a high intensity discharge lamp and method of manufacture wherein, through reliance on the different density of gases to isolate the sealed atmosphere, the arc tube end (38) may remain open to an uncontrolled atmosphere during both the step of gas full and the subsequent step of hermetically sealing the tube by a pinch seal at the lead assembly (32). Further, the final pressure of the fill gas sealed within the arc tube (12) may be controlled by controlling the temperature of the fill gas during sealing thus obviating the need to employ a pump to control the fill gas pressure.