Method of making discharge lamp having blow-molded arc tube ends

Abstract

In arc discharge lamps containing a mixture of metals and halogen, and especially where an unvaporized excess of one metal is present, lamp color is very sensitive to end chamber shape. Color uniformity in production lamps using quartz arc tubes varying appreciably in diameter and wall thickness is greatly improved by molding end chambers of constant size and shape in the ends. The chamber may be formed at the time the end is pinched and the electrodes sealed in by using pinching jaws having a mold defining portion and momentarily pressurizing the arc tube to expand the heated and still plastic end into the mold. In production all lamps will have their ends expanded or belled to some extent, more in lamps close to the minimum diameter limit and less in lamps close to the maximum diameter limit.

Dependencies are inferred from the claim text.